Plant Communities of Baja California, Mexico

Plant Ecol (2008) 196:27–60 DOI 10.1007/s11258-007-9334-5

A phytosociological and phytogeographical survey of the coastal vegetation of western North America. Part I: plant communities of Baja California, Mexico

Manuel Peinado Æ Juan Luis Aguirre Æ Jose´ Delgadillo Æ Miguel A´ ngel Macı´as

Received: 10 February 2006 / Accepted: 20 June 2007 / Published online: 18 July 2007 Ó Springer Science+Business Media B.V. 2007

Abstract Through tabular and average linkage seven new orders and four new classes: Allenrolfeetea cluster analyses, 737 phytosociological releve´s were occidentalis, Atriplici julaceae–Frankenietea palmeri, classified. Based on these releve´s, we described and Euphorbio leucophyllae–Sporoboletea virginici and typified the associations, alliances, orders, and classes Achyronichio cooperi–Abronietea villosae. grouping the coastal plant communities of the Baja California peninsula. Diagnostic tables, classification Keywords Beach vegetation Braun-Blanquet by average linkage clustering, and climatic, edaphic, approach Maritime cliffs Plant association Sand and biogeographical data were used to establish dune vegetation Syntaxonomy floristic affinities among these syntaxa and to interpret their distributions. Syntaxa were characterized by their floristic composition, physiognomy, and biogeo- Introduction graphical distribution, along with their positions in halophilous and psammophilous gradients. Thirty- Since 1989, we have been surveying the phytosoci- three associations were identified, of which 22 are ology of western North America. During the course here described for the first time. Our syntaxonomical of our investigations, we have always maintained an proposal includes descriptions of nine new alliances, attitude of extreme caution when making syntaxonomical proposals, acquiring a large and statistically significant number of releve´s before suggesting M. Peinado (&) syntaxonomic units of a high hierarchical level. This Departamento de Biologıá Vegetal, Universidad de is the approach we adopted in two phytosociological Alcala´, Alcala´ de Henares, Madrid 28871, Spain surveys of the boreal forests (Peinado et al. 1998) and e-mail: [email protected] chionophilous vegetation of the west of North J. L. Aguirre America (Peinado et al. 2005b, c). Using the same Ca´tedra de Medio Ambiente, Universidad de Alcala´, approach, we now embark on the study of the coastal Alcala´ de Henares, Madrid 28871, Spain vegetation of the North American Pacific. So far, we J. Delgadillo have selected 3,259 releve´s related to coastal plant Facultad de Ciencias, Universidad Autońoma de Baja communities. These releve´s, along with those of California, Ensenada, BC, Mexico future fieldwork, will form the basis of a series of publications that we now initiate with this phytoso- M. A´ . Macıás Departamento de Ciencias Ambientales, Universidad de ciological analysis of the coastal vegetation of Baja Guadalajara, Jalisco, Mexico California. 123 28 Plant Ecol (2008) 196:27–60

The term coastal vegetation, as applied in the in Delgadillo (1995) and Peinado et al. (1994a, b, present article, refers to azonal vegetation directly 1995a, d, 1997, 2007). affected by marine breezes, mainly including beach, From a phytogeographical standpoint (Fig. 1), the dune, and sea bluff vegetation. Outside the scope of peninsula is transitional between the Holarctic and this article is the vegetation of saltmarshes and Neotropical Kingdoms (Peinado et al. 1994b, 1995a). mangroves, since these have been the subjects of The former only appears in the northwestern extreme previous studies (Delgadillo et al. 1992; Peinado of the peninsula, corresponding to the Martirense et al. 1994c, 1995b, c). Province of the Californian Region. The rest of the peninsula sustains a flora and vegetation clearly related to the Neotropical Kingdom and Xerophytic- Study area Mexican Region sensu Rzedowski (1978). In this region, also named Sonoran by Takhtajan (1986), we Baja California is a narrow peninsula ranging from recognize three provinces: Coloradan, corresponding the southern boundary of California southeasterly to the subcontinental territories of the northeastern about 1,300 km to its tip at Cabo San Lucas (Fig. 1). corner of Baja California (Sanfelipense sector), The study area comprises the 3,510 km of the Bajacalifornian (hyperoceanic and oceanic areas peninsula’s coast: the Pacific coast, from the estuary occupying most of the peninsula) and Sanlucan, of the river Tijuana (32°340 N–117°080W) to Cabo corresponding to the Cape Region, the portion of the Pulmo (23°270 N–109°260 W) and the Gulf coast, peninsula south of the La Paz fault (Lenz 1992; Leoń which extends from Cabo Pulmo to the lower basin of de la Luz et al. 2000). the river Colorado (32°400 N–114°450 W). The present location of beaches and dunes is largely the result of eustatic sea level rising during Methods the past 20,000 years, in the post-Wisconsin (Del- court and Delcourt 1993). Beach and dune sands The present phytosociological investigations were related to marine transgression, since the Late performed according to the concepts described by Wisconsin are referred as Flandrian by Cooper Westhoff and van der Maarel (1973) and Braun- (1967). Pre-Flandrian dunes occur inland and support Blanquet (1979). Data on the vegetation were shrubs and succulent scrubs, physiognomically and obtained from releve´s recorded in the field between floristically related to the shrubby vegetation of the 1990 and 2005. In total, 737 releve´s (including 325 Flandrian dunes. vascular plant taxa) were obtained from 132 sites According to the bioclimatic classification of (Fig. 1 and Appendix 1). The releve´ plots at each site Rivas-Martıńez (2005), there are three bioclimatic were selected with respect to homogeneity of phys- belts along the Baja California coast, two of which ical features, vegetation structure and species dom- correspond to the Mediterranean macroclimate and inance. Depending on the community, plot sizes one to the Tropical macroclimate (Fig. 1). Zonal ranged from 200 m2 to 4 m2 (Table 4). Cover/ vegetation in coastal areas correspond to sclerophyl- abundance data for all vascular plants were recorded lous chaparrals and succulent scrubs along the using the Braun-Blanquet (1979) scale. The environ- Thermomediterranean and Inframediterranean belts, mental data collected from each site were: altitude, respectively, and to different types of thermotropical- slope, aspect, soil type, and geological substratum. desert vegetation in the rest of the peninsula. The Edaphic and geological data were obtained from exception is the southern tip where tropical rains Anonymous (1995, 2001). Plants were identified, as promote the growth of communities dominated by far as possible in the field and critical specimens microphyllous trees and shrubs, floristically and collected for subsequent laboratory identification. physiognomically related to the Sinaloan thornscrubs These plants were deposited in the herbarium of the or ‘‘bosque espinoso’’ of continental Mexico. Addi- Universidad Autońoma de Baja California tional information on climax vegetation can be found (BCMEX).

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Fig. 1 Phytogeographical divisions of Baja California (Roman numerals) sites sampled (see Appendix 1) and climatograms for six representative sites. Californian Region: I, Martirense province (sectors: Ia, Juarezense; Ib, Martirense). Xerophytic- Mexican Region: II, Bajacalifornian province (sectors: IIa, Vizcaıńo; IIb, Angelino-Loretano; IIc, Magdalenan). III Sanlucan province. IV, Coloradan province (Sanfelipense sector). Phytogeographical divisions after Peinado et al. 1994b, modified. Abbreviations for climatograms: Ar, Arid ombrotype. Im, Inframediterranean thermotype. P, annual precipitation (mm). Sa, Semiarid ombrotype. T, Mean annual temperature (°C). Tm, Thermomediterranean thermotype. Tt, Thermotropical thermotype. Climograms and bioclimatic types according to Rivas-Martıńez (2005)

The next step was to recompile the information et al. 1966), Isocoma (Nesom 1991) and Opuntia available for the distribution area of each taxon (Rebman 1995). According to their distribution areas, recorded in the ﬁeld. In order to do this, bibliograph- the registered taxa were distributed in ﬁfteen phyto- ical sources were used (Cooper 1936; Munz and Keck geographical elements (Table 1; Appendix 2; Peinado 1973; Macdonald and Barbour 1974; Barbour et al. et al. 2007). 1975; Breckon and Barbour 1974; Johnson 1977; Following the principles of complementarity anal- Wiggins 1980; Barbour and Johnson 1988; Hickman ysis (Kent and Ballard 1988), we used numerical and 1993; Delgadillo 1995; Flora of North America phytosociological methods to classify our releve´s. Editorial Committee 1993–2005) along with distri- For the numerical analysis, Braun-Blanquet cover/ bution maps obtained from the databases CalFlora abundance values were ordinally transformed: + was (2004), VAST (2005) and USDA (2005). Plant replaced by 1, 1 by 2, 2 by 4, 3 by 6, 4 by 7 and 5 was nomenclature usually follows USDA, except for the replaced by 8. Analyses were performed using SPSS Baja California endemics (Wiggins 1980; Lenz v13.0 software, starting with a matrix that included 1992), Agave (Gentry 1978), Helianthus (Heiser each plant recorded in the releve´s, together with their 123 30 Plant Ecol (2008) 196:27–60

Table 1 Distribution Abbr. Phytogeographical element Distribution range ranges of the phytogeographical elements BAJ Bajacalifornian Bajacalifornian Province (1) used in this work CAL Californian Californian Province (2) HOL Holarctic Holarctic Kingdom (3) INT Introduced Non-native taxa MAD Madrean Madrean Region (3) MAG Magdalenan Magdalenan Sector (1) MAR Martirense Martirense Province (1) NAS North American–South American Both Americas (excluding NEO taxa) NEO Neotropical Neotropical Kingdom (3) NOA North American North America (1) See Fig. 1. (2) Sensu PAN Pantropical Pantropical taxa Takhtajan (1986), but SAN Sanlucan Sanlucan Province (1) excluding MAR taxa. (3) Sensu Takhtajan (l.c.). (4) SON Sonoran Sonoran Province (4) Sensu Takhtajan (l.c.), but VIZ Vizcainoan Vizcaıńo Sector (1) excluding taxa endemic to WES Western North-American West of the Rocky Mountains Baja California respective cover indices. Classification was based on M. phyllanthoides growing on saline soils were square Euclidean distances calculated by an Average included in the ALKA matrix, while the 58 releve´s Linkage Clustering method of similarity (ALC). ALC for sandy soils were included in the SAND matrix. is one of the most frequently used methods in We then independently subjected each of these new vegetation similarity analysis, in which the process of matrices (ALKA, 210 releve´s and 102 taxa; SAND, fusion is based on the minimum average distance 474 releve´s and 249 taxa; and SUCC, with the between individuals and groups (Kent and Coker initial 53 releve´s including 78 taxa) to further 1992). The advantages of the ALC over single or numerical analysis, to define floristic groups in complete linkage clustering were summarized by more detail. For each of the resultant 34 groups, a Sneath and Sokal (1973), Gauch (1982) and Digby synoptic coefficient of frequency (Presence-Classes and Kempton (1987). of Braun-Blanquet 1979) was computed. In this In the first stage, the 737 releve´s generated four way, three synoptic phytosociological tables were large clusters: (1) ALKA, with 191 releve´s, most of elaborated by scoring species for percentage classes which from alkaline soils; (2) SAND, 416 releve´s and cover/abundance degrees. sampled in sandy areas; (3) SUCC, 53 releve´s These primary tables served to order the groups dominated by plants of coastal succulent scrub; and and determine their floristic composition as a basis (4) MAYT, 77 releve´s dominated by Maytenus for further rearrangement along phytosociological phyllanthoides. Next, the floristic composition of criteria (Westhoff and van der Maarel 1973). As a each of these clusters was phytosociologically result, 41 floristic groups were finally obtained. These analyzed and three new matrices were constructed were interpreted as associations and used to generate because this analysis of the releve´s revealed that M. a new presence table, which served to establish phyllanthoides dominated two types of releve´s. The relationships among associations and form the basis first, which was very species poor, was codominat- for the final syntaxonomical treatment. For nomen- ed by halophilous species commonly found in the clatural standards, we referred to the International ALKA group. In the second one, whose floristic Code of Phytosociological Nomenclature (ICPN; diversity was greater, halophilous species were Weber et al. 2000). Alliances, orders and classes lacking or rare, while there was an abundance of are here defined by their combination of diagnostic plants common to the SAND group. Accordingly, species, which include character- and differential- in the subsequent ALC, the 19 releve´s containing species (Beeftink 1965, and Article 8 of the ICPN).

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Nomenclatural type releve´s for each association and Thermomediterranean-Semiarid and Inframediterra- diagnoses for high syntaxa are shown in Appendix 3. nean-Arid belts. In Table 3 the releve´s of the ECOT Excluded are syntaxa belonging to the classes group were assigned to the groups DUDL, JULA or Prosopido torreyanae–Fouquierietea splendentis EUPH according to their geographical position and and Pachycereo pecten-aborigini–Lysilometea divar- floristic similarities with one or another group. icatae, since these are being analyzed in a revision The ALC performed on 474 releve´s of the SAND we are presently preparing. matrix yielded 21 clusterings (Fig. 2b). The LYCI group gathered all the releve´s dominated by Lycium richii, a nanophanerophyte that thrives on primary Results dunes in which there is direct salt-spray influence. The small tree Encelia ventorum, endemic to the Classification (Tables 2, 3) sandy soils and dunes of the Vizcaıńo sector, is the commonest species of the ENCE group. E. ventorum The dendrogram in Fig. 2a shows the four large also appears in the SPHA group, but the releve´sof clusters identified in the first analysis (737 releve´s this group were recorded in sea bluffs of the and 325 taxa). Table 2 is a summary table showing northwestern El Vizcaıńo peninsula. Sphaeralcea the main floristic differences among these initial fulva is fairly endemic to this area. clusters. The releve´s of the cluster MAYT were then Along the Pacific coast, between Tijuana and Isla distributed between matrices ALKA and SAND. The Magdalena, Isocoma menziesii var. menziesii and next ALC performed on the new three matrices Helianthus niveus subsp. niveus form communities yielded 34 clusterings (Figs. 2b–d). immediately behind the dune crests occupied by L. The ALC of the ALKA matrix generated eight richii and/or E. ventorum. These communities were large groupings (Fig. 2d). The MAY2 group clustered brought together in the groups ANEM (from Astrag- together all the releve´s dominated by Maytenus alus anemophilus), BRYA (from Lotus bryantii), and phyllanthoides. The POLY group comprised releve´s NIVE (from Helianthus niveus). Releve´s including dominated by Atriplex polycarpa, a species typical of Isocoma menziesii var. vernonioides clustered to- the drier margins of alkali sinks, whose damper gether in the VERN group. bottoms are dominated by communities of the The ATMA group was comprised of four releve´s hydrohalophyte Allenrolfea occidentalis (ALLE dominated by Atriplex magdalenae, a species typical group). of disturbed areas of the tropical beaches of Baja The JULA group was dominated by Atriplex California. Other releve´s including A. magdalenae julacea and Frankenia palmeri and gathered most dispersed in other groups, mainly in ABRO and of the releve´s derived from the alkaline plains of the MAGD. The ABRO and MAGD groups gathered the northern Vizcaıńo sector. The LINE group was also foredune releve´s, the first of both being quite dominated by F. palmeri, but Atriplex canescens exclusively dominated by Abronia maritima, and subsp. linearis replaces A. julacea in this group. the second by Sarcostemma arenarium and Astrag- While these two groups are almost exclusively alus magdalenae. A. maritima is also abundant in the dominated by chamaephytes (A. canescens subsp. PALA group, but this group brought together a set of linearis¸ A. julacea and F. palmeri), chamaephytes releve´s recorded on the Gulf coast. Palafoxia linearis and nanophanerophytes coexist in the remaining and Dalea tinctoria var. tinctoria, endemic to the groups and greatest covers are achieved by the latter, Gulf coast, characterized this group. mainly Lycium californicum. The group EUPH Yucca valida, Fouquieria diguetii and the large brought together a group of releve´s recorded in the cacti Stenocereus gummosus, S. thurberi, Pachycere- coastal plains of the southern Vizcaıńo sector. The us pringlei and P. schottii are the more character- group DUDL is floristically defined by the presence species of the YUCC group. The AMBL group of Dudleya cultrata, a local endemic confined to the gathered all the releve´s dominated by the small Martirtense sector. The group ECOT was found to be therophyte Amblyopappus pusillus. Communities of a transition group, clustering 14 releve´s taken north mesotropical winter-annuals were gathered in the and south of El Rosario, an ecotone between the group CHAE (from Chaenactis lacera). The group 123 32 Plant Ecol (2008) 196:27–60

Table 2 Classiﬁcation results: percentage distributions of the most frequent taxa differentiating four clusterings obtained from the ﬁrst ALC Clusterings MAYT SAND ALKA SUCC MAYT SAND ALKA SUCC No. of releve´s 77 416 191 53 77 416 191 53 No. of taxa 83 214 99 78 83 214 99 78

MAYT ALKA Maytenus phyllantoides 100 – – – Frankenia palmeri – 5 60 – Lycium fremontii 48 – – – Atriplex julacea –164836 var. congestum Pachycereus pringlei 32 – – – Lycium californicum – – 39 – Jatropha cuneata 27 – – – Allenrolfea occidentalis 27 – 33 – Arthrocnemum 25 – – – Euphorbia misera – – 28 40 subterminale Antigonon leptopus 22 – – – Atriplex polycarpa – – 20 – Cyrtocarpa edulis 21 – – – Encelia farinosa – – 17 – var. phenocodonta Lycium andersonii 16 – – – Suaeda taxifolia – – 13 – var. andersonii Stenocereus gummosus 14 – – – Atriplex canescens subsp. linearis – – 11 – Bursera microphylla 13 – – – Dudleya cultrata – – 10 28 Monanthochloe littoralis 13 – 6 – Ambrosia dumosa ––8– Lemaireocereus thurberi 12 – – – Stillingia linearifolia ––7– var. littoralis Lycium megacarpum 9–––Viguiera microphylla ––7– Opuntia cholla 9–––Atriplex barclayana ––634 subsp. barclayana Sesuvium portulacastrum 9––– –––– Dyssodia speciosa 8 – – – SUCC – – – – Atriplex magdalenae 55––Aesculus parryi –––70 Ambrosia chenopodifolia –––70 SAND Agave shawii subsp. shawii –––64 Euphorbia leucophylla 926––Acalypha californica –––60 Jouvea pilosa 17 22 – – Allium haematochiton –––51 Abronia maritima –20––Bergerocactus emoryi –––47 Oenothera drummondii –17––Artemisia californica –––43 var. thalassaphila Proboscidea althaefolia 616––Sairocarpus nuttallianus –––41 Sporobolus virginicus 10 13 – – Dudleya lanceolata –––38 Isocoma menziesii –11––Astragalus trichopodus –––36 var. menziesii Lycium richii –11––Stenocereus gummosus –––34 Helianthus niveus –11––Justicia californica –––32 subsp. niveus Palafoxia linearis 510––Cneoridium dumosum –––30 Encelia ventorum –8––Dudleya attenuata subsp. orcuttii –––30 Mesembryanthemum –8––Echinocereus maritimus –––30 crystallinum Croton californicus –8––Eriogonum fasciculatum –––30 var. fasciculatum

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Table 2 continued Clusterings MAYT SAND ALKA SUCC MAYT SAND ALKA SUCC No. of releve´s 77 416 191 53 77 416 191 53 No. of taxa 83 214 99 78 83 214 99 78

Ipomoea pes-caprae –8––Cuscuta veatchii –––28 subsp. brasiliensis Asclepias subulata –7––Mammillaria dioica –––28 Drymaria holosteoides –7––Rosa minutifolia –––28 var. crassifolia Froelichia interrupta –6––Encelia californica –––24 var. californica Atriplex canescens –6––Ephedra californica –––24 subsp. canescens Chaenactis lacera –5––Dudleya pulverulenta –––23 subsp. pulverulenta Camissonia crassifolia –5––Eriogonum fasciculatum –––17 var. ﬂavoviride Abbreviations: ALKA, alkaline group; MAYT, Maytenus phyllanthoides group; SAND, sandy soils group; SUCC, succulent scrub group

ERRA (from Errazurizia megacarpa) collated seven subsp. shawii. Groups CNEO (from Cneoridium releve´s recorded in coastal dunes of the Sanfelipense dumosum, a Thermomediterranean endemic) and sector. ERIO (from Eriogonum fastigiatum, an Inframedi- Releve´s of the beaches and dunes of the Sanlucan terranean endemic) are dominated by succulents and province formed well-defined groups. Group DRYM drought deciduous shrubs. Group ECOT comprises brought together releve´s dominated by Drymaria releve´s of the Mediterranean-mesotropical ecotone. holosteoides var. crassifolia, a pioneer on the lower In Table 3, the releve´s of the ECOT group were and flooded parts of the beaches. Sporobolus virgin- assigned to other SUCC groups according to floristic icus, a pioneer of non-flooded beaches, was the similarities with each. commonest plant of the SPOR group. S. virginicus forms mound behind which form small wind-shel- Endemism in the coastal plant communities tered microhabitats occupied by Ipomoea pes-caprae (Table 3) subsp. brasiliensis (IPOM group). Beyond the beach vegetation, starts the foredune zonation. Jouvea Of the 325 vascular plants recorded in the study zone, pilosa (JOUV group) is the main foredune builder 302 (93%) are native taxa. Of these, 106 (35%) are of the San Lucan province. Flagged shrubs of endemic to Baja California and a further 12 are Maytenus phyllanthoides (MAY1 group) usually described as fairly endemic, since they also slightly thrive on the dunes with water-table influence, penetrate into the neighboring San Diego County. whereas the backdunes are occupied by communities Fifty-five Out of the 106 Baja California endemics composed of multi-trunked trees and shrubs. Cyrto- (52%) are plants distributed more or less uniformly carpa edulis is the most common member of this across all the tropical portion of the peninsula group (CYRT). (Tropical Bajacalifornian endemics). The remaining The ALC performed on releve´s of the SUCC peninsular endemics are shared among three areas of matrix yielded five clusterings (Fig. 2b). The group high levels of endemism: the Martirense and Sanlu- STEN is dominated by the large cactus Stenocereus can provinces, and the Vizcaıńo sector. A fourth less gummosus. The group ROSA is characterized by the important area is the Magdalenan sector, which has combination of deciduous low trees (Aesculus parryi) two local endemics. and shrubs (Rosa minutifolia), together with succu- The Martirense province is where elements of lents such as Bergerocactus emory and Agave shawii Mediterranean distribution exclusively concentrate 123 34 123

Table 3 Classiﬁcation results: summarized data for the number of infra-generic taxa on each clustering according to 15 phytogeographical elements (columns; for abbreviations see Table 1) Phytog. elements HOL NAS NOA WES MAD SON CAL MAR BAJ VIZ MGD SAN PAN NEO INT Total

CLUST. MARTIRENSE CNEO 0 0 0 0 (17) 41 (4) 9 (9) 21 (7) 17 (4) 10 (1) 2 0 0 0 0 0 42 ERIO 0 0 0 0 (17) 32 (7) 13 (7) 13 (14) 26 (3) 6 (4) 7 0 0 (1) 2 (1) 2 0 54 ROSA 0 0 0 0 (12) 39 0 (8) 26 (8) 26 (2) 6 (1) 3 0 0 0 0 0 31 STEN 0 0 0 0 (15) 44 (1) 3 (4) 12 (8) 23 (4) 12 (2) 6 0 0 0 0 0 34 DUDL 0 (2) 5 0 0 (20) 49 (3) 7 (1) 2 (9) 22 (1) 2 (2) 5 0 0 0 0 (3) 7 41 NIVE 0 (1) 4 (2) 8 0 (11) 44 (2) 8 (1) 4 (3) 12 (2) 8 (1) 4 0 0 0 0 (2) 8 25 LYCI 0 0 (3) 7 0 (15) 37 (3) 7 (3) 7 (7) 17 (4) 10 (3) 7 (1) 2 0 0 (1) 2 0 40 ANEM 0 0 0 0 (4) 57 0 0 (1) 14 0 0 0 0 0 0 (2) 29 7 VERN 0 (1) 4 (3) 12 0 (9) 36 (2) 8 (1) 4 (3) 12 (2) 8 (2) 8 0 0 0 0 (2) 8 25 AMBL (1) 3 (1) 3 (1) 3 (2) 7 (3) 10 0 (3) 10 0 0 0 0 0 0 (1) 3 (18) 60 30 VIZCAI´NO JULA 0 0 (4) 11 0 (9) 24 (5) 13 0 0 (7) 19 (7) 19 0 0 0 (3) 8 (2) 5 37 EUPH (1) 2 (2) 3 (2) 3 0 (14) 25 (17) 30 0 0 (5) 9 (11) 19 0 0 0 (3) 5 (2) 3 57 POLY 0 (1) 2 (1) 2 0 (8) 19 (14) 33 0 0 (8) 19 (6) 14 0 0 0 (4) 9 (1) 2 43 SPHA 0 (1) 3 (1) 3 0 (10) 32 (7) 23 0 0 (4) 13 (5) 16 0 0 0 (2) 6 (1) 3 31 ENCE 0 0 (1) 4 0 (9) 34 (6) 22 0 0 (5) 18 (4) 15 0 0 0 (2) 7 0 27 YUCC 0 (2) 3 (1) 2 0 (7) 11 (29) 47 0 0 (15) 25 (4) 7 0 0 0 (2) 3 (1) 2 61 CHAE 0 (2) 9 0 0 (6) 26 (6) 26 0 0 (2) 9 (3) 13 0 0 0 (2) 9 (2) 9 23 ATMA 0 0 (1) 7 0 (4) 29 (1) 7 0 0 (3) 21 (3) 21 0 0 (1) 7 0 (1) 7 14 MAGDALENAN BRYA 0 0 0 0 (3) 21 (3) 21 0 0 (3) 21 (1) 7 (2) 14 0 (1) 7 (1) 7 0 14 MAGD 0 0 0 0 (3) 33 (1) 11 0 0 (1) 11 0 (2) 22 0 0 (1) 11 (1) 11 9 GULF PALA 0 0 0 0 (2) 13 (8) 53 0 0 (3) 20 0 0 (1) 7 0 (1) 7 0 15 LINE 0 0 0 0 (3) 37 (3) 37 0 0 (1) 12 0 0 0 0 0 (1) 12 8 ln cl(08 196:27–60 (2008) Ecol Plant ERRA 0 0 0 0 (1) 11 (6) 67 0 0 (1) 11 0 0 0 0 (1) 11 0 9 PENINSULAR ALLE 0 (1) 6 (3) 19 0 (7) 44 (2) 12 0 (1) 6 0 0 0 0 1 0 (1) 6 16 MAY1 0 (2) 29 (1) 14 0 (1) 14 (1) 14 0 0 0 0 0 0 0 (2) 29 0 7 ABRO 0 (2) 8 (2) 8 0 (3) 11 (4) 15 (1) 4 (1) 4 (3) 11 (1) 4 0 0 (1) 4 (4) 15 (4) 15 26 Plant Ecol (2008) 196:27–60 35

(Californian and Martirense endemics). Besides this, the clusterings of the Martirense province also show significant proportions of endemics linked to the tropical climate zone (Sonoran and Tropical Bajacal- ifornian endemics) and of elements shared by tropical and Mediterranean areas (Madrean endemics). In some groups of essentially Martirense distribution, the presence of endemic plants of El Vizcaıńo is also significant. In the groups of the Vizcaıńo sector there are 59 peninsular endemics, of which 18 are local endemics. Two groups (BRYA and MAGD) are characterized by having two Magdalenan endemics: Cynanchum peninsulare and Dalea brandegeei. The clusterings included in the Gulf and Peninsu- lar groups have no local endemics. The first gathers three clusters whose releve´s were taken on the Gulf coast. The Peninsular group includes clusterings with the common feature that they represent sets of releve´s spread along the entire coast (ABRO) or only along the tropical coast (ALLE and MAY1). The data from our releve´s revealed two outstanding features of the releve´s taken on the Sanlucan province. First, its endemic richness: the Sanlucan coastal strand harbors 51 Baja California endemics, of which 19 are Sanlucan endemics. Secondly, relationships with the Neotropical flora and with South America are the most intense of all the groups, and include plants dominant on beaches and dunes, such as Batis maritima, Ipomoea costellata, I. pes-caprea subsp. brasiliensis, I. stolonifera, Jouvea pilosa, Maytenus phyllanthoides, Portulaca pilosa, Sporobolus virginicus and Stegnosperma halimifolium.

Discussion

Phytogeographical discussion

The most outstanding ﬂoristic feature of the Marti- rense groups is the combination of elements of both Mediterranean and tropical distribution, a combination that is typical of the transition zones or ecotones. The vegetation of the Martirense province has been SPORIPOMJOUVMAY2 0CYRT 0 2 (10) 0SANDY (1) SOILS 14 0 0 (1)SUCCULENTS 1 0 0 0 (8)Total 3 0 0 0 (1) (5) 0 3 2 0 (1) (1) 5 (3) 1 0 1 0 (1) (32) 1 (6) 13 0 32 0 (1) (66) 1 0 (2) 26 (5) 6 6 (10) 3 (2) 0 (9) 29 0 (11) 4 (31) (8) 31 40 2 0considered (3) (9) 1 (1) 0 4 (26) 0 3 0 33 0 (46) 14 (46) (8) (11) 18 10 31 (75) 23 (2) (14) (9) 0 10 18 4 (23) 0 0 7 0 (17) a 22 (2) (19) 1distinctive 6 (20) 0 (5) 26 (7) 14 9 0 (19) (55) 8 17 0 (3) 0 (18) (4) 1 5 0 5 0 (15) 6 (6) (2) 0 17 1 transitional (22) (3) 0 9 16 0 (19) 0 6 249 (1) 0 5 0 (12) (5) 15 1 (4) (9) 21 0 26 (18) 5 0 (1) 14 0 (23) 0 7 0type (1) 1 (8) 10 325 0 (11) (7) (1) 30 20 1between 19 0 (3) 43 0 0 0 (7) 0 19 78 35 the 78 0 7 36 desertscrub of the South (Bajacalifornian province) and the sclerophyllous scrub characteristic of the continued semiarid Mediterranean climates (Southern Califor- nian province) of the North (Westman 1983; Peinado

Table 3 Phytog. elementsSANLUCAN DRYM HOL NAS 0MATRIXES NOA WES 0 MAD ALKALINE SON 0 CAL 0Each line 0 gives the number MAR (2) of 2 taxa (in brackets) and (4) the BAJ 0 4 percentage (rounded) of the (1) total 1 number VIZ of (1) taxa (26) 33 (last 25 column) MGD (23)et 22 al. SAN 0 (2) 21994a PAN NEO (8) 8 0, INT (15) 151995a Total (10) 10 0). 0 The 0 southern 0 (1) 0 1 (6) 6boundaries (2) 67 (4) 4 0 102 0 of Van 0 3 123 36 Plant Ecol (2008) 196:27–60

Fig. 2 Dendrograms yielded by average linkage clustering: (a) matrix and including 58 releve´s of the MAYT group. (d) Starting from the initial matrix (737 releve´s). (b) Starting from Starting from the alkaline–soil matrix and including 19 releve´s the succulent-scrub group. (c) Starting from the sandy–soil of the MAYT group

Dyke’s (1919) California faunal zone, Dice’s (1943) humid than other sectors of the Bajacalifornian Californian biotic province, Howell’s (1957) Califor- province (Peinado et al. 2005a). As a result, in the nia flora province, and Bailey’s (1989) Mediterranean northern part of the sector (from approximately division appear around 30°300 N, and the flora and Guerrero Negro southwards to Punta Abreojos), a vegetation of this area have long been considered hyperoceanic Inframediterranean bioclimate appears, ‘‘transitional’’ (Shreve 1936; Shreve and Wiggins which is inexistent in the rest of that sector. These 1964). Breckon and Barbour (1974) reported that the bioclimatic conditions allow the penetration along the Baja California beach vegetation underwent a floris- cooler coast of elements of northern origin (Madrean tic shift close to 30°300 N, while Johnson (1977) and Martirense) and viceversa. described this zone as one showing the striking The releve´s for the groups of the Magdalenan replacement of herbaceous dune species between the sector were taken south of Punta Abreojos, where the ‘‘northern’’ (or Mediterranean) and ‘‘central’’ (or Inframediterranean belt dominant in the northern half tropical) regions. of El Vizcaıńo converts to the thermotropical, which The Vizcaıńo sector forms a clearly defined dominates from Punta Abreojos southwards. Accord- floristic, biogeographical unit (Wiggins 1969; Peina- ing to Ko¨ppen’s climatic classification, Punta Abreo- do et al. 1994b, 2005a). The dune systems of El jos is a transient area from Bwk (Cold Desert) to Bwh Vizcaıńo and their alkaline postdune plains harbor (Hot Desert) due to the increasing mean annual 183 plants endemic to Baja California, 89 of which temperature, which is accompanied by a change in do not exist elsewhere in the peninsula (Peinado et al. eco-floristic zones, whereby the warmer south arid 2005a). However, most of the Martirense groups zone gives way to the northern arid zone (Breckon show a small number of Vizcaıńo endemics. Due to and Barbour 1974). The coastal boundary between its exposure to lower temperatures and fog from the the cooler Vizcaıńo and the warmer Magdalenan cool California Current (Hastings and Turner 1965; phytogeographical sectors of the Baja Californian Turner and Brown 1982; Anonymous 1995), the province occurs approximately 20’ south of Punta northern coast of El Vizcaıńo is colder and more Abreojos, at Bahıá de San Juanico, where Shreve and 123 Plant Ecol (2008) 196:27–60 37

Wiggins (1964) located the transition between the Syntaxonomic discussion (Tables 4–6) Vizcaıńo and Magdalenan subdivisions of the Sono- ran Desert. The alkaline soil group is characterized by a set of The clusterings included in the Gulf sector and in plants, Allenrolfea occidentalis, Frankenia palmeri, the Peninsular set have no local endemics. Percent- Atriplex julacea, and Lycium californicum. The ages of Sonoran and Tropical Bajacalifornian ele- ALKA cluster showed a clear separation of cluster- ments in the Gulf clusterings are among the highest ings corresponding to plants growing on solonchaks recorded. Groups ERRA and LINE were derived (wet entisols or aquents in U.S. Soil Taxonomy; see from the coasts of the Sanfelipense sector, a zone Steila 1993) dominated by Allenrolfea occidentalis whose subcontinental tropical bioclimate extends (MAY2 and ALLE) from remaining clusterings, a uninterrupted across the entire Xerophytic-Mexican separation based on the strong dominance of A. Region, resulting in its high proportion of Sonoran occidentalis and on its practical absence from the rest elements and lack of an original endemic floristic of the groups (ass. 1, 2, 3). Allenrolfea occidentalis is component. The PALA group includes releve´s for considered a hydrohalophyte, living on saline aquents the Angelino-Loretano sector, a narrow coastal band where the water table remains within about 1 m connecting the Coloradan and Sanlucan provinces above the soil surface (West 1988). It withstands the linked to the Vizcaıńo sector via the Sierra de la greatest salinity in the halosere of the North Amer- Giganta. The flora of this sector thus presents one of ican saline lakes, where it forms a band of fruticose the highest percentages of Tropical Bajacalifornian vegetation in direct contact with hypersaline crusts endemics, among which we could mention the devoid of plants (Burk 1988; Vaseck and Barbour abundant group of endemics shared with the San- 1988; Sawyer and Keeler-Wolf 1995; Peinado et al. lucan province. Within the Peninsular group, the 2005a). Indeed, according to our field observations ALLE clustering has the highest proportion of and in contrast to other alkaline soil communities Madrean, Sonoran, and North American species dominated by Frankenia palmeri or Lycium californ- (76% of its taxa), because the communities of icum, the surface soil in the communities dominated Allenrolfea occidentalis extend from Baja California by A. occidentalis, usually stays wet all summer. to the Mohave and Great Basin deserts (Keeler-Wolf The first approach to a syntaxonomic classification 2007). In the MAY1 group, however, elements with of the North American communities living on Neotropical and North American-South American solonchaks was made by Knapp (1957), who pro- relations predominate and together make up 57% of posed the class Allenrolfeetea occidentalis and the its flora. order Allenrolfeetalia occidentalis to group them. The Sanlucan province has long been known to Since this proposal was not based on published be an important area of biogeographical differen- releve´s, Knapp’s syntaxa are not validly published tiation (Baird 1860; Cope 1873; Brandegee 1891; (ICPN; Weber et al. 2000). However, applying ICPN Dice 1943; Wiggins 1980). The climax vegetation Articles 6 and 46 and Recommendation 46d, the on lowlands is comprised of Sinaloan thornscrubs publication is here made effective (Appendix 3). belonging to Zonobiome II, a clear difference with Communities dominated by A. occidentalis are respect to the rest of the peninsula, whose climax species-poor, due to the extreme ecological condi- vegetation belongs to Zonobiomes III and IV tions they endure. Hence, A. occidentalis is the only (Peinado et al. 1994a). The floristic catalogue of character-species of the class. the Sanlucan province contains 1053 vascular The ALLE clustering (less two releve´s moved to plants (Lenz 1992), 293 of which are peninsular association 8) corresponds to two associations endemics, including 132 local endemics (Peinado already described: Allenrolfeetum occidentalis Pei- et al. 1994b). The history of geological isolation of nado et al. 1994 and Suaedo taxifoliae–Allenrolfee- the Sanlucan province as an island, since its tum occidentalis Peinado et al. 2005. The relatively formation in the late Jurassic-early Cretaceous up high presence of Frankenia palmeri and Atriplex until Plio-Pleistocene times (Durham and Allison julacea in the latter association is attributed to the 1960), could help explain the original nature of this fact that this community appears on beaches lying province. 0.5–1 m above the average tide level, allowing 123 38 123 Table 4 Character-combination (ch: character-species; di: differential-species), vegetation structure, habitat, bioclimatic (Tt: thermotype; Ot: ombrotype), phytogeographical (units as in Fig. 1), edaphic and other ecological features of the coastal associations of Baja California Association Character-combination Vegetation structure Habitat Tt Ot Phytogeo. Soils Slope Aspect Plot Cover

1. Allenrolfeetum Allenrolfea occidentalis Saltbush shrubland (na) Alkali sinks Tt Ar-Sa II, III, IV SK 0 In 30 54 occidentalis 2. Suaedo taxifoliae– A. occidentalis, Suaeda Saltbush shrubland (na) Alkali beaches Tt Ar IIa AR(ak) 0 Wi 25 88 Allenrolfeetum taxifolia (di) occidentalis 3. Allenrolfeo occidentalis– A. occidentalis, Maytenus Mangrove shrubland Tidal Tt Ar-Sa IIb,c; III SK 0 In 130 88 Maytenetum phyllanthoides (di) (me) phyllanthoidis 4. Atriplici linearis– Atriplex canescens subsp. Saltbush shrubland (ch) Alkali plains Im-Tt Ar-Ha IV SL 0 In 50 38 Frankenietum palmeri linearis, Frankenia palmeri 5. Atriplici julaceae– Atriplex julacea, F. palmeri Saltbush shrubland (ch) Alkali plains Im-Tt Ar-Ha IIa SL 0 In 40 41 Frankenietum palmeri 6. Euphorbio miserae– Euphorbia misera, Lycium Saltbush shrubland Alkali dunes Im-Tt Ar IIa AR(ak) 0 Le 80 46 Lycietum californici californicum (na/me) 7. Dudleyo cultratae– Dudleya cultrata (ch), Saltbush shrubland Alkali dunes Im-Tm Ar Ib AR(ak) 1 Le 80 74 Lycietum californici L. californicum (na/me) 8. Encelio phenocodontae– Encelia californica var. Saltbush shrubland (na) Alkali sinks Im-Tt Ar IIa RE(pt) 0 In 130 56 Atriplicetum polycarpae phenocodonta (ch), Atriplex polycarpa (ch) 9. Isocomo menziesii– Ambrosia chamissonis (di), Psammophilous Foredune Tm Sa Ib AR 0 Le 30 72 Ambrosietum Isocoma menziesii var. shrubland (na/me) hillocks chamissonis menziesii 10. Loto bryanthii– Lotus bryanthii (ch), Psammophilous Secondary Tt Ar IIc AR 0 Le 84 69 Isocometum menziesii I. menziesii var. menziesii shrubland (na/me) backdunes 11. Heliantho nivei– Helianthus niveus subsp. Subhalophilous Wet interdune Tm-Im Ar-Sa Ib AR 0 Le 60 60 Isocometum vernonioidis niveus, I. menziesii var. shrubland (na/me) depressions vernonioides (ch) ln cl(08 196:27–60 (2008) Ecol Plant 12. Camissonio H. niveus subsp. niveus, I. Psammophilous Secondary Tt-Im Ar-Sa Ib AR 0 Le 90 60 crassifoliae– menziesii var. menziesii shrubland (ch/na) backdunes Helianthetum nivei 13. Heliantho nivei– H. niveus subsp. niveus, Psammophilous Sea bluffs Tm-Im Ar Ib AR(ak) 1–4 Le 40 58 Astragaletum anemophili Astragalus anemophilus shrubland (ch/na) (ch) 14. Camissonio Camissonia crassifolia, Open shrubland (me) Secondary Im-Tt Ar IIa RE(eu) 1 Wi 80 58 crassifoliae–Encelietum Encelia ventorum backdunes ventori ln cl(08 196:27–60 (2008) Ecol Plant Table 4 continued Association Character-combination Vegetation structure Habitat Tt Ot Phytogeo. Soils Slope Aspect Plot Cover

15. Sphaeralceo fulvae– Sphaeralcea fulva (ch), E. Open shrubland Sea bluffs Im Ar IIa AR(ak) 1–3 Wi 80 60 Encelietum ventori ventorum (me) 16. Ephedro californicae– Ephedra californica (di), Thorny shrubland Primary backdunes Tm-Im Sa Ib AR 1 Wi 88 81 Lycietum richii Lycium richii (na/me) 17. Lycietum brevipedis L. richii Thorny shrubland Primary backdunes Tt Ar-Sa IIa, c AR 1–2 Wi 45 86 (na/me) 18. Cneoridio dumosi– Cneoridium dumosum (ch), Succulent shrubland Rocky places Tm Sa Ib LI 1 Wi 100 61 Agavetum shawii Agave shawii subsp. (na/me) shawii 19. Bergerocacto emoryi– Bergerocactus emoryi, A. Succulent shrubland Climax vegetation Im Sa Ib RE, XE 0–1 Wi 100 63 Agavetum shawii shawii subsp. shawii (na/me) 20. Roso minutifoliae– Rosa minutifolia, Aesculus Dry deciduous Climax vegetation Im Sa Ib RE, XE 0 Le 75 68 Aesculetum parryi parryi (di) chaparral (na/me) 21. Trixido californicae– Trixis californica (ch), Succulent Rocky places Tm-Im Sa Ib LI 0–2 In 50 84 Stenocereetum gummosi Stenocereus gummosus shrubland (me) (di) 22. Atriplici leucophyllae– Atriplex leucophylla (ch), Prostrate perennial Foredune hillocks Tm-Im Sar Ib AR 1–4 Wi 20 77 Abronietum maritimae Abronia maritima forbs (xy) 23. Abronietum maritimae A. maritima, Sesuvium Prostrate perennial Foredune hillocks Im-Tt Ar-Ha IIa, c AR 1–4 Wi 20 73 portulacastrum forbs (xy) 24. Sarcostemmato Astragalus magdalenae var. Psammophilous Foredune hillocks Tt Ar IIc AR 1–3 Le 90 50 arenarii–Astragaletum magdalenae (ch), Dalea shrubland (ch) magdalenae brandegeei (ch) 25. Atriplicetum Atriplex magdalenae (ch) Psammophilous Disturbed places Tt Ar-Ha II AR 0 In 67 50 magdalenae shrubland (na) 26. Palafoxio linearis– Dalea tinctoria var. Psammophilous Secondary backdunes Tt Ar IIb AR 0–1 Le 100 52 Daleetum tinctoriae tinctoria (ch) shrubland (na) 27. Euphorbio Euphorbia leucophylla, Pioneer herbaceous Flooded beaches Tt Ar-Sa III AR 0 Wi 18 36 leucophyllae– Drymaria holosteoides vegetation (th) Drymarietum crassifoliae var. crassifolia 28. Euphorbio E. leucophylla, D. Psammophilous Embryonic dunes Tt Ar-Sa III AR 0 Wi 20 45 leucophyllae–Jouveetum holosteoides var. grassland (rh) pilosae crassifolia, Jouvea pilosa 29. Sporobolo virginici– Ipomoea pes-caprae subsp. Psammophilous Depressions on Tt Ar-Sa III AR 0 Le 55 71 123 Ipomoeetum brasiliensis brasiliensis (ch) perennials (rh) beaches 30. Ipomoeo imperati– Ipomoea imperati (ch), Psammophilous Primary dune ridges Tt Ar-Sa III AR 1 Wi 65 65 Jouveetum pilosae Jouvea pilosa

grassland (rh) 39 40 123 Table 4 continued Association Character-combination Vegetation structure Habitat Tt Ot Phytogeo. Soils Slope Aspect Plot Cover

31. Daleo anthonyi– Dalea divaricata var. Psammophilous Secondary dune ridges Tt Ar-Sa III AR 2 Wi 73 71 Jouveetum pilosae anthonyi (ch), J. pilosa shrubland (ch/rh) 32. Daleo maritimae– Dalea maritima (ch), J. Psammophilous Secondary dune ridges Tt Ar III AR 2 Wi 79 69 Jouveetum pilosae pilosa shrubland (ch/rh) 33. Sporobolus virginicus Sporobolus virginicus Psammophilous Embryonic dunes Tt Ar-Sa IIb; III AR 0 Wi 36 62 community pioneer grassland (rh) 34. Maytenetum Maytenus phyllanthoides Open shrubland Sea-facing rocky Tt Ar-Sa IIb, c; III LI 1–2 Wi 50 100 phyllanthoidis (me) slopes 35. Lycio congesti– Lycium congestum (di), M. Closed and ﬂagged Dune slopes Tt Ar-Sa III AR 1–2 Wi 160 83 Maytenetum phyllanthoides shrubland phyllanthoidis (me/ma) 36. Cyrtocarpo edulis– Cyrtocarpa edulis (di), M. Closed shrubland Dune slopes Tt Ar-Sa III AR 1–2 Le 200 94 Maytenetum phyllanthoides (me/ma) phyllanthoidis 37. Jatropho cordatae– Jatropha cordata, C. edulis, Sarcocaulescent Sandy plains Tt Ar-Sa III AR 0 Le 180 74 Cyrtocarpetum edulis Antigonum leptopus thornshrubland (ma) 38. Plantagini ovatae– Plantago ovata, Chaenactis Winter-annual Sandy-alkali plains Im-Tt Ar IIb AR(ak) 0 In 5 43 Chaenactidetum lacerae lacera (ch), Dyssodia grassland (th) anthemidifolia (ch) 39. Amblyopappo pusilli– Amblyopappus pusillus Winter-annual Disturbed places Im-Tm Ar-Sa Ib RE, XE 0 In 4 84 Mesembryanthemetum (ch), grassland (th) crystallini Mesembryanthemum crystallinum 40. Errazurizio Errazurizia megacarpa Creosote bush Dunes Tt Ar-Ha IV AR 0 Wi 85 60 megacarpae–Ephedretum (ch), Ephedra trifurca shrubland (na/me) trifurcae (ch), Larrea tridentata 41. Yucco validae– Yucca valida (ch), Open Yucca- Sandy-alkali plains Tt Ar-Ha IIb RE(ak) 0 In 150 58 ln cl(08 196:27–60 (2008) Ecol Plant Fouquierietum diguetii Fouquieria diguetii, L. woodland tridentata (me/ma) Abbreviations for biotypes of dominant strata (Vegetation structure) = ch: chamaephytic (<25 cm); ma: macrophanerophytic (2–4 m); me: mesophanerophytic (1–2 m); na: nanophanerophytic (0,25–1 m); rh: rhizomatous geophytic; th: therophytic; xy: xylopodic (taprooted geophytes). Abbreviations for bioclimatic data = Ar: Arid; Ha: Hyperarid; Im: Inframediterranean; Sa: Semiarid; Tm: Thermomediterranean; Tt: Thermotropical. Abbreviations for soils: ak: alkaline; AR: Arenosols; LI: Lithosols; RE: Regosols; SK: Solonchak; SL: Solonetz; XE: Xerosols. Slope classes (degrees) = 0: 0–10; 1: 11–20; 2: 21–30; 3: 31–40; 4: >41. Abbreviations for aspect: In: Indifferent; Le: Leeward (S-SE); Ww: Windward (N-NW). Plot: mean of the plot sizes (square meters). Cover: mean cover (%) ln cl(08 196:27–60 (2008) Ecol Plant Table 5 Syntaxonomic results: synoptic table of the coastal associations of Baja California ordered as in Table 4 (columns)

Associations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 No. of relevés 44 14 22 15 32 33 21 32 5 13 8 21 13 24 12 11 21 15 17 8 13 11 27 11 9 14 14 21 20 29 22 7 23 12 25 22 11 26 15 17 7

Allenrolfea occidentalis 100.3 100.4 74.1 ...... Suaeda taxifolia . 92.1 . . . . 33.1 . . . 13.1 .1. . . . 14...... Arthrocnemum subterminale . . 95.2 ...... Monanthochloe littoralis 18.1 . 47.1 . . .2. . . . 13...... Frankenia palmeri . 46.1 . 100.2 100.2 100.2 43.2 38.1 . . . 19.1 . 29.2 33.1 . 24.1 40.1 . 13.2 ...... Atriplex julacea . 38.1 . . 81.2 88.1 90.2 50.1 . . 25.2 52.2 62.2 . 42.1 36.2 100.2 33.1 76.1 13.2 15.+ . . . 11.+ ...... 18.1 . Lycium californicum . 15.2 . . 28.1 61.2 100.3 69.2 . . 13.1 . . . 17.2 . . 20.1 . 13.1 ...... 65.2 . Euphorbia misera . . . . 16.1 100.2 52.2 13.1 ...... 47.1 . 13.2 100.1 ...... Atriplex polycarpa . . . .2. . . 100...... 12.1 . Atriplex barclayana subsp. barclayana . . . 13.1 . . . . .1...... 33.1 76...... Atriplex canescens subsp. linearis . . . 100.2 . . . 19.1 ...... Dudleya cultrata ...... 90.1 . . . 25.+ 33.1 ...... 82.1 13.2 ...... Mirabilis californica var. californica ...... 38.1 ...... Encelia farinosa var. phenocodonta . . . . . 12.+ . 88.2 .2. . . . 17...... Viguiera microphylla . . . . . 12.1 . 25.+ ...... Camissonia crassifolia ...... 50.1 . 85.1 13.1 57.1 . 80.1 75.2 . 24.1 .+...... 11...... Isocoma menziesii var. menziesii ...... 80.2 100.3 13.1 62.3 54.2 . . 36.2 14.1 13.+ 18.+ 13.+ ...... Lycium richii ...... 19.2 . . . 38.2 10.+ . 17.3 25.1 100.3 100.4 ...... Helianthus niveus subsp. niveus ...... 60.2 . 75.2 90.2 85.2 . . 27.2 ...... Atriplex canescens subsp. canescens . 23.2 ...... 20.1 . 50.1 10.1 . 25.2 17.+ 45.2 19.3 .1...... 11...... Ephedra californica ...... 14.2 . . 25.+ 33.+ . . . 100.2 . 40.2 29.2 . 15.+ ...... Sarcostemma arenarium ...... 54.1 13.1 . . . 25.1 18.2 ...... Distichlis spicata ...... 2.0.3 . 38.2 .1. . . 14...... Lotus distichus ...... 25.+ 33.2 ...... Camissonia cheiranthifolia subsp. suffruticosa ...... 38.1 19.1 ...... 18.+ ...... Lotus bryantii ...... 85.3 ...... Isocoma menziesii var. vernonioides ...... 100.3 ...... Lotus rigidus ...... 25.+ 10.+ ...... Encelia ventorum ...... 13.+ ...... 100.3 75.1 ...... Sphaeralcea fulva .1...... 13...... 100.1 ...... 18.+ . Astragalus anemophilus ...... 3. . . 1.00...... Ambrosia chamissonis ...... 100.2 ...... 18.1 ...... Carpobrotus chilensis ...... 100.3 . 25.1 . 46.2 ...... 27.+ ...... Agave shawii subsp. shawii ...... 87.2 82.2 63.2 15.+ ...... Bergerocactus emoryi ...... 67.2 41.+ 50.1 31.+ ...... Ambrosia chenopodifolia ...... 14.1 . . . . 10.+ . . . . . 73.2 82.2 38.2 69.1 ...... Artemisia californica ...... 80.1 41.1 13.2 23.+ ...... Eriogonum fasciculatum var. fasciculatum ...... 33.1 24.1 13.2 54.+ ...... Aesculus parryi ...... 80.2 100.2 100.3 ...... Allium haematochiton ...... 67.1 94.1 13.1 ...... Cuscuta veatchii ...... 27.2 59.3 13.1 ...... Encelia californica var. californica ...... 47.1 29.+ 13.2 ...... Dudleya attenuata subsp. orcuttii ...... 40.1 35.1 . 31.+ ...... Dudleya lanceolata .1...... 1.3...... 20.1 59.+ . 54.1 ...... Echinocereus maritimus ...... 47.1 29.1 . 31.+ ...... Ferocactus viridescens ...... 20.1 35.1 . 15.+ ...... Rosa minutifolia ...... 100.2 46.2 ...... Mammillaria dioica ...... 1.9.+ .+. . 1.0. . . . . 20.1 . . 85.1 ...... Viguiera laciniata ...... 13.1 54.1 ...... Harfordia macroptera ...... 33.1 ...... Lotus scoparius var. scoparius ...... 27.1 ...... Mammillaria brandegeei ...... 24.1 . 15.+ ...... Cleome isomeris ...... 29.2 13.1 ...... Malosma laurina ...... 27.+ . 38.2 ...... Opuntia littoralis ...... 18.2 . 13.+ . 25.+ ...... Acalypha californica ...... 100.2 100.2 ...... Sairocarpus nuttallianus ...... 80.2 59.1 ...... Dudleya pulverulenta subsp. pulverulenta ...... 33.1 41.1 ...... Eriogonum fasciculatum var. flavoviride ...... 20.1 35.1 ...... Eriogonum scalare ...... 40.1 12.1 ...... Haplopappus rosaricus ...... 13.1 24.1 ...... Cneoridium dumosum ...... 100.2 ...... Calystegia macrostegia subsp. tenuifolia ...... 67.1 29.1 ...... Eriogonum fastigiatum ...... 47.1 ...... Astragalus trichopodus ...... 27.2 88.2 ......

123 Ferocactus fordii var. fordii ...... 35.1 13.+ ...... Galium angustifolium subsp. angustifolium ...... 35.+ ...... Idria columnaris ...... 24.2 ...... Malvastrum coromendalianum ...... 24.3 ...... Melica frutescens ...... 24.2 ......

Pentagramma triangularis subsp. viscosa ...... 50.1 ...... 41 Ribes tortuosum ...... 25.1 15.1 ...... Stenocereus gummosus .+...... 10...... 24.+ . 100.3 ...... 42.2 16.1 27.1 . . . 94.2 . 42 123 Table 5 continued

Simmondsia chinensis ...... 25.1 46.3 ...... 2.3.3 . . . . Trixis californica ...... 62.1 ...... Dudleya ingens ...... 23.+ ...... Abronia maritima . 15.1 ...... 13.2 ...... 100.4 5.3 73.+ 33.1 79.4 . . . 12.+ . 43.+ 13.1 ...... Atriplex leucophylla ...... 27.1 100.3 ...... Euphorbia leucophylla ...... 30.1 . . 29.1 78.2 81.1 60.1 85.1 68.1 43.3 43.1 ... 32.+ . . . . Jouvea pilosa ...... 100.3 15.1 100.3 100.3 100.3 . . 16.1 41.1 64.2 . . . . Sporobolus virginicus ...... 30.1 . . . . . 55.1 . . 14.+ 100.3 . 28.1 23.1 18.1 . . . . Amaranthus watsonii ...... 85.+ ...... 2.9.2 ... . . 71.+ ...... Chamaesyce micromera ...... 15.1 91.+ . 43.1 ...... 18.1 . . . . Croton californicus ...... 20.1 . . 10.1 ...... 15.1 82.2 . 29.1 ... . 55.2 . .+...... 29. Oenothera drummondii var. thalassaphila ...... 85.1 48.1 30.2 68.2 68.1 . ... . 36.2 . . . Atriplex magdalenae ...... 15.1 ...... 100.3 29.1 ... . . 86.2 . . 23.2 18.1 . . . . Proboscidea althaefolia ...... 31.+ ...... 29.1 . . . 71.1 86.1 57.1 . 20.2 . 64.1 . . . . Sesuvium portulacastrum . . 37.1 .1. . . . . 15...... 37.2 ...... Heliotropium curassavicum var. oculatum ...... 22.1 ...... Astragalus fastidius ...... 29.2 ...... 33.1 ...... Astragalus magdalaneae var. magdalenae ...... 100.2 ...... Cynanchum peninsulare ...... 64.+ ...... Dalea brandegeei ...... 31.+ ...... 18.1 ...... Dalea tinctoria var. tinctoria ...... 3. . . 1.00...... Drymaria holosteoides var. crassifolia ...... +. . . . 1.00.2 48...... Scaveola plumieri ...... 1. . . . . 1.4...... Ipomoea pes-caprae subsp. brasiliensis ...... 100.3 26.1 ...... Cenchrus palmeri ...... 17.1 14.1 14.+ ...... Palafoxia linearis ...... 93.1 . . 30.+ 35.1 23.2 57.2 13.2 ..16.1 . . . . . Ipomoea imperati ...... 1...... 44.1 . . 17...... Perityle crassifolia var. crassifolia ...... 29.+ . 29.1 ...... Froelichia interrupta ...... 35.1 27.1 . 17.1 ...... Asclepias subulata ...... 35.1 64.1 . ... . 27.2 . . . Physalis glabra ...... 17.+ . . ..12.+ . . . . . Portulaca pilosa ...... 15.1 14.+ ...... Dalea divaricata subsp. anthonyi ...... 95.2 . ... 18.+ 36.3 . . . Dalea maritima ...... +. . . 2.1...... 100.2 ... . 18.1 . . . Encelia farinosa var. radians ...... 86.1 ... 18.+ . . . . Coulterella capitata ...... 43.1 ...... Argythamnia brandegeei var. intonsa ...... 43.3 ...... Euphorbia polycarpa var. johnstonii ...... 43.+ ...... Wislizenia refracta var. mammillata ...... 29.+ ...... Krameria paucifolia ...... 57.1 . . . 18.1 . . 12.1 . Lycium andersonii ...... 19.1 ...... 31.1 ...... 100.1 ...... Maytenus phyllantoides . . 100.4 ...... 100.4 100.5 100.3 18.1 . . . . Lycium megacarpum ...... 20.2 ...... Pachycereus pringlei .1...... 1.3. .+...... 12...... 17.+ 36.+ 59.1 . . . 88.1 . Antigonon leptopus ...... 12.2 18.1 . . . 32.1 41.2 18.2 . . . . Bursera microphylla ...... 25.1 12.1 18.2 . . . 12.+ . Prosopis palmeri ...... 18.1 36.3 . . . . Castela peninsularis ...... 12.1 23.3 27.3 . . . . Opuntia cholla ...... 18.+ . . 25.1 12.+ . . . . 18.2 . Stegnosperma halimifolium ...... Bursera cerasifolia ...... 14.3 . . . 23.+ . . . . . Bursera fagaroides var. elongata ...... 36.2 . . . . Condaliopsis rigida ...... 45.3 . . . . Jatropha cordata ...... 12.+ . . . . . 23.1 73.1 . . . . Lycium fremontii var. congestum ...... 84.3 77.2 18.1 . . . . Jatropha cuneata ...... 2.1.+ ...... 20.2 64.1 . . . 12.1 . Cyrtocarpa edulis ...... 100.2 100.3 . . . . Dyssodia speciosa ...... 18.+ . . . . . Bursera epinnata ...... 18.1 . . . .

Bursera filicifolia ...... 18.1 . . . . 196:27–60 (2008) Ecol Plant Caesalpinia placida ...... 18.1 . . . . Cardiospermum corindum ...... 23.1 . . . . . Porophyllum porphyreum ...... 23.3 . . . . . Pithecellobium confine ...... 27.2 . . . . Acacia peninsularis ...... 27.2 . . . . Sapindus saponaria ...... 27.2 . . . . Lemaireocereus thurberi var. littoralis ...... 36.+ . . . 12.+ . Prosopis velutina ...... 25.1 ...... Chaenactis lacera .1. . . 2.2.1 18. .2. . . 29...... 33.2 ...... 88.2 . . . Plantago ovata . . . . 13.1 .+. . . . . 10...... 92.1 . . . Dyssodia anthemidifolia . . . . 13.1 ...... 62.2 . . . Phaseolus acutifolius var. latifolius ...... 54.1 . 29.1 . . 17.1 ...... 2.7.1 . . . . . 73.1 . . . Perityle emoryi ...... 25.1 ...... 46.2 . . . Abronia umbellata subsp. umbellata .1. . . . . 14...... 54.1 . . . Achyronychia cooperi ...... 38.1 . . . Cryptantha maritima var. maritima .1. . . . . 1.4. .1. . 24...... 31.1 . . . Crassula connata var. eremica ...... 27.1 . . . Spergularia bocconii ...... 19.1 . . . ln cl(08 196:27–60 (2008) Ecol Plant Table 5 continued

Nemacaulis denudata ...... 14.1 . . 17.1 ...... 15.1 . . . Dithyrea californica var. clinata ...... 12.1 . . . Amblyopappus pusillus ...... 14.1 ...... 100.2 . . Mesembryanthemum crystallinum . . . . . 21.1 48.1 . . . 13.2 43.2 38.3 ...... 81.2 73.2 . . Mesembryanthemum nodiflorum ...... 47.2 . . Pterostegia drymarioides ...... 40.3 . . Sonchus tenerrimus ...... 20.2 . . Lepidium nitidum ...... 33.1 . . Melilotus indica ...... 33.1 . . Poa annua ...... 27.1 . . Cistanthe maritima ...... 13.1 . . Bromus rubens ...... 13.+ . . Bromus arizonicus ...... 13.+ . . Malva parviflora ...... 13.+ . . Yucca valida ...... 13.1 .1. . . . . 25...... 100.1 . Fouquieria diguetii .1. . . . 30...... 33.2 . . 18.2 . . 100.2 . Jatropha cinerea ...... 24.1 . 13.+ .1. . . . 17...... 25.2 . . 18.3 . . 82.1 . Larrea tridentata var. tridentata ...... 25.2 ...... 76.1 100.2 Opuntia ciribe ...... 71.1 . Pachycereus schottii var. schottti .+. . . . . 29.1 13...... 1.7.+ . . . . 59.+ . Opuntia invicta ...... 53.+ . Mammillaria hutchinsoniana ...... 41.+ . Pedilanthus macrocarpus ...... 2.5.+ . . . . 41.+ . Ambrosia magdalenae .+...... 13...... 29.1 . Echinocereus engelmannii var. engelmannii ...... 29.+ . Tillandsia recurvata ...... 29.1 . Parkinsonia microphylla ...... 24.+ . Encelia palmeri ...... 24.+ . Ferocactus gracilis var. gracilis ...... 24.+ . Ephedra trifurca ...... 100.2 Pleuraphis rigida ...... 100.2 Ambrosia dumosa . . . 27.+ . 12.1 . 25.+ . . . 10.+ . 13.4 ...... 86.1 Errazurizia megacarpa .1...... 19...... 71.1 Stephanomeria pauciflora ...... 57.+ Tiquilia plicata ...... 29.+ Justicia californica ...... 13.1 ...... 29.1 ...... 12.1 ...... Dichelostemma congestum . . . . 16.1 ...... 13.1 ...... Stillingia linearifolia ...... 10.+ . 13.2 ...... Haplopappus berberidis ...... 14.+ . . . 13.2 ......

Other taxa: Lycium carolinianum (16.2, ass. 3). Camissonia cardiophylla subsp. cedrosensis (13.1, ass. 5). Pachycormus discolor var. veatchiana (12.2, ass. 6). Triteleiopsis palmeri (12.+, ass. 6). Lupinus concinnus var. brevior (13.+, ass. 8). Nicolletia trifida (19.+, ass. 8). Salsola tragus (20.1, ass. 9). Cardionema ramosissimum (13.1 ass. 11). Encelia californica var. asperifolia (13.2, ass. 11). Tamarix racemosa (13.1, ass. 11). Encelia halimifolia (13.1, ass. 14). Dalea mollis subsp. mollis (17.2, ass. 14). Astragalus harbisonii (13.2, ass. 14). Sphaeralcea ambigua (23.1, ass. 21). Salvia munzii (15.1, ass. 21). Haplopappus sonorensis (36.+, ass. 26). Atamisquea marginata, Encelia farinosa var. farinosa (12-+, ass. 40). Opuntia molesta (12.1, ass. 40). Solanum hindsianum (18.1, ass. 40). Asclepias albicans (14.1, ass. 41). 123 43 44 Plant Ecol (2008) 196:27–60

Table 6 Diagnosis and character-combination of the new high syntaxa Syntaxa Ass.

I. Allenrolfeetea occidentalis. I.1. Allenrolfeetalia occidentalis. I.1a. Allenrolfeion occidentalis 1–3 Hydrohalophilous phanerophytic and chamaephytic vegetation growing on alkaline aquents of the Xerophytic- Mexican and Great Basin regions. BIO: Mm, Sm, Mt, Tt, Ar, Ha, Sa. Allenrolfea occidentalis (ch). II. Atriplici julaceae-Frankenietea palmeri Chamaephytic and nanophanerophytic coastal vegetation of Baja California and neighboring areas. PHY: I, II, IV. BIO: Tm, Im, Mt, Tt, Ar, Ha, Sa. Atriplex julacea (ch), Frankenia palmeri (ch). II.1. Atriplici julaceae-Frankenietalia palmeri. II.1a. Atriplici julaceae-Frankenion palmeri 4–8 Xerohalophilous associations growing on soils rich in exchangeable sodium, principally solonetzs, but also in regosols and xerosols with a sodium phase. PHY: I, II, IV. BIO: Tm, Im, Mt, Tt, Ar, Ha, Sa. Ambrosia chenopodifolia (di), Atriplex barclayana subsp. barclayana and subsp. sonorae, A. polycarpa, Dudleya cultrata (ch), Euphorbia misera (ch), Lycium californicum (ch), L. megacarpum. II.2. Camissonio crassifoliae-Isocometalia menziesii Oceanic dune-scrubs: Mesophanerophytic, nanophanerophytic and chamaephytic vegetation growing on aeolian sands. PHY: I, IIa, IIc. BIO: Im, Tm, Tt, Ar, Sa. Atriplex canescens subsp. canescens, Camissonia crassifolia (ch), C. cheiranthifolia subsp. suffruticosa (ch), Ephedra californica, Lotus distichus (ch), Sarcostemma arenarium. II.2a. Heliantho nivei-Isocomion menziesii 9–13 Fruticose (chamaephytic and nanophanerophytic) backdune associations usually living in areas protected from the direct effects of salt spray by communities of Encelion ventori and/or Lycion richii. PHY and BIO: see order. Helianthus niveus subsp. niveus (ch), Isocoma menziesii subsp. menziesii (ch). II.2b Encelion ventori 14–15 Open shrublands (mesophanerophytic) on parabolic dunes and sea bluffs. PHY: IIa. BIO: Im, Tt, Ar. Encelia ventorum (ch). II.2c. Lycion richii 16–17 Thorny shrublands (nanophanerophytic) occupying primary backdunes subjected to the direct influence of the salt spray and are found immediately behind foredunes harboring Abronia maritima at the windiest sites or close to the beaches of protected coastlines. PHY: I, IIa, IIc (also in the Southern Californian province). BIO: Im, Tm, Tt, Ar, Ha, Sa. Lycium richii (ch). II.3. Bergerocacto emoryi-Agavetalia shawii 18–21 Coastal succulent scrubs. Climax vegetation of the Inframediterranean belt and edaphoxerophilous vegetation (drier sites, steep southern slopes, shallow stony soils, sea bluffs, and others habitats unfavorable for the growth of zonal chaparrals) along the coastal Thermomediterranean belt. PHY: I. Aesculus parryi (ch), Agave shawii subsp. shawii (ch), Artemisia californica, Bergerocactus emoryi (ch), Cleome isomeris, Cneoridium dumosum, Echinocereus maritimus (ch), Eriogonum fasciculatum var. fasciculatum and var. flavoviride, Lotus scoparius subsp. scoparius, Malosma laurina, Mammillaria dioica, Opuntia littoralis (ch), Rhus integrifolia, Rosa minutifolia (ch), Salvia munzii, Trixis californica, Viguiera laciniata (ch). III. Euphorbio leucophyllae-Sporoboletea virginici Vegetation dominated by perennial plants, mainly by tap-rooted, succulent perennials, rhizomatous grasses, and prostrate hemicryptophytes and chamaephytes, which act as pioneer colonizers of beaches and foredunes builders from southern California to Mesoamerica. BIO: Im, Mm, Tm, It, Tt, Ar, Ha, Sa (also under dry to humid ombroclimates in Mesoamerica). Chamaecyse micromera, Croton californicum (ch), Euphorbia leucophylla (ch), Froelichia interrupta (ch), Houstonia mucronata (ch), Ipomoea imperati (ch), Ipomoea pes- caprae subsp. brasiliensis, Palafoxia linearis (ch), Proboscidea althaefolia (ch), Portulaca pilosa (ch), Scaevola plumieri, Sporobolus virginicus, Wislizenia refracta (ch). III.1. Abronietalia maritimae Foredune vegetation of the northwestern Pacific coast, from the Southern Californian and Martirense provinces (Californian region), southward to the tropical coasts of Baja California, Sonora and Sinaloa (Xerophytic- Mexican region). BIO: Im, Mm, Tm, Tt. Abronia maritima (ch).

123 Plant Ecol (2008) 196:27–60 45

Table 6 Diagnosis and character-combination of the new high syntaxa Syntaxa Ass.

III.1a. Atriplici leucophyllae–Abronion maritimae 22 Foredune vegetation of the Southern Californian and Martirense provinces. BIO: Im, Mm, Tm. Abronia maritima, Atriplex leucophylla (ch), Ambrosia chamisssonis (di), Cakile maritima (di), Camissonia cheiranthifolia subsp. cheiranthifolia, Cardionema ramosissimum (di), Carpobrotus chilensis (di). III.1b. Palafoxio linearis–Abronion maritimae 23–26 Tropical foredune vegetation of the Xerophytic-Mexican region, but excluding the Sanlucan communities, which belong to the alliance III.2a. BIO: It, Tt, Ar, Ha. Abronia maritima, Amaranthus watsonii (di), Astragalus magdalenae var. magdalenae (ch), Atriplex magdalenae, Euphorbia leucophylla (di), Palafoxia linearis (ch), Porophyllum maritimum (ch), Sporobolus virginicus. III.2. Sporobolo virginici-Jouveetalia pilosae Foredune vegetation of Tt and It Pacific zones whose ombroclimates range from upper-semiarid to humid. Its area spreads along the Sanlucan coasts of Baja California and, in Mesoamerica, extends from the arid Sinaloan coasts southwards to Costa Rica. Jouvea pilosa. III.2a. Oenothero talassaphilae-Jouveion pilosae 27–33 Foredune vegetation endemic of the Sanlucan province. BIO: Tt, Sa. Coulterella capitata (ch), Dalea divaricata var. anthonyi, D. maritima, Drymaria holosteoides var. crassifolia (ch), Encelia farinosa var. radians (ch), Oenothera drummondii var. talassaphila (ch), Perityle crassifolia (ch). IV. Achyronichio cooperi-Abronietea villosae Winter-annual communities of the Xerohytic-Mexican region. BIO: Im, Mt, Tt, Ar, Ha. Ch.: Abronia gracilis, A. villosa var. villosa, Achyronychia cooperi, Antheropeas lanosum, A. wallacei, Argythamnia serrata, Atriplex elegans, Boerhavia intermedia, Calycoseris wrightii, Camissonia claviformis subsp. claviformis, Chorizanthe brevicornu var. brevicornu, C. rigida, Coreocarpus parthenoides, Cryptantha angustifolia, Dicoria canescens subsp. canescens, Dithyrea californica var. californica, Drymaria viscosa, Eriogonum reniforme, E. thomasii, Euphorbia eriantha, Geraea canescens var. canescens, Loeflingia squarrosa subsp. cactorum, Lotus salsuginosus var. brevivexillus, L. strigosus var. tomentellus, Lupinus arizonicus subsp. arizonicus var. arizonicus, L. concinnus subsp. orcuttii, Mohavea confertiflora, Monolepis nuttalliana, Monoptilon bellioides, Nama demissum var. demissum, Nemacaulis denudata var. gracilis, Nemacladus glanduliferus var. glanduliferus, Oenothera deltoides subsp. deltoides, Palafoxia arida var. arida, Parthenice mollis, Pectis papposa, Pectocarya peninsularis, Phacelia crenulata s.l., Plantago ovata, Salvia columbariae var. columbariae, Senecio mohavensis, Sphaeralcea coulteri, S. orcuttii, Stillingia spinulosa, Stylocline micropoides. IV.1. Nicolletio trifidae-Verbenetalia bajacalifornicae. IV.1a. Chaenactido lacerae-Dyssodion anthemidifoliae 38 Winter-annual communities endemic to Baja California. PHY: II, III, IV. BIO:: Im, Tt, Im, Tt, Mt, Ar, Ha. Ch: Bouteloua annua, Cassia confinis, Castilleja bryanthii, Cenchrus palmeri, Chorizanthe flava, Cryptantha angelica, C. echinosepala, C. fastigiata, C. grayii, Dalea vetula, Dithyrea californica var. clinata, Dryopetalon palmeri, Dyssodia anthemidifolia, Eriogonum scalare, Euphorbia heterophylla var. eriocarpa, Houstonia brevipes, Linanthus vizcainensis, Lyrocarpa xantii, Lythrum bryantii, Malacothrix xantii, Mecadornis exilis, Mentzelia adhaerens, Mirabilis oligantha, Nicolletia trifida, Pectis ambigua, Perityle aurea, P. lobata, Petalostemon evanescens, Polygala desertorum, Salvia similis, Sibara laxa, Spharealcea axillaris, S. hainesii, Stachys tenerrima, Verbena bajacalifornica, V. shrevei. Abbreviations and associations (Ass.) as in Table 4. Other abbreviations: PHY and BIO: Phytogeograhical and bioclimatic features, respectively. It: Infratropical thermotype. Mm: Mesomediterranean thermotype. Mt: Mesotropical thermotype. PHY: Phytogeograhical features. Sm: Supramediterranean thermotype

F. palmeri and A. julacea to anchor their roots in the the new thermotropical association Allenrolfeo occi- dry top soil, while the deeper roots of Suaeda dentalis–Maytenetum phyllanthoidis, in which Mayt- taxifolia and A. occidentalis reach the wet saline enus phyllanthoides appears as a low, branched shrub gley layer. Tidal mangrove shrubs (MAY2 clustering (up to 1.5 m tall), growing in saline soils of plus three releve´s moved from MAY1) correspond to depressions close to the sea that are ﬂooded by the

123 46 Plant Ecol (2008) 196:27–60 higher tides or whose soils show clear effects of miserae–Lycietum californici (EUPH clustering more gleyzation produced by brackish water-table layers. other 8 releve´s from ECOT and 3 from JULA The rest of the alkaline soil clusterings corre- clusterings). The habitat of the association Dudleyo sponds to xerohalophytic communities that flourish in cultratae–Lycietum californici on the alkaline dune soils rich in exchangeable sodium, principally solo- complexes of the Inframediterranean belt is shown in netzs, but also in regosols and xerosols with a sodium Fig. 3a. Euphorbio miserae–Lycietum californici also phase. Several of the plants growing in xero-alkaline thriving in alkaline arenosols is endemic to the soils are dominant but not exclusive in their respec- Vizcaıńo sector (Fig. 3b). tive associations (4–8). In Baja California, xero- The new order Bergerocacto emoryi–Agavetalia alkaline soils arise from rocks, such as limolites, shawii physiognomically corresponds to the so-called lutites, and sandstones originated in the Upper coastal succulent scrub (Mooney and Harrison 1972; Cretaceous and Lower Tertiary. Today, these rocks Axelrod 1988; Westman 1983; Zippin and Vanderw- massively outcrop only in some plains and mesas ier 1994), and syntaxonomically to the alliance close to the sea in the northwest, between Punta Agavion shawii Rivas-Martıńez 1997, representing Colonet and Malarrimo, north of the El Vizcaıńo the climax vegetation of the Inframediterranean belt peninsula, and between Bahıá Asuncioń and Punta and a type of edaphoxerophilous vegetation along the Abreojos, to the south of this peninsula (Anonymous coastal Thermomediterranean belt (Delgadillo 1995; 1995, 2001). Where these outcrops prevail, the soils Peinado et al. 1995a; Rivas-Martıńez 1997). Besides are highly selective for the vegetation, since high two associations already described, Roso minutifoli- sodium concentrations provoke functional distur- ae–Aesculetum parryi Peinado et al. 1995 (ROSA bances and injuries that few plants are able to tolerate clustering plus one releve´ from ECOT) and Berge- (Larcher 2003). In this setting, communities of the rocacto emoryi–Agavetum shawii Peinado et al. 1995 alkaline soil group dominate exclusively. In the rest (ERIO clustering plus one releve´ from ECOT), within of the peninsula, these ancient sediments are buried this order, we recognize two new associations: by younger deposits, mainly by Tertiary and Quater- Cneoridio dumosi–Agavetum shawii (CNEO cluster- nary volcanic rocks, and by aeolian sandy layers. ing two more releve´s from ECOT) and Trixido Hence, the constant presence of alkali indicators, californicae–Stenocereetum gummosi (STEN cluster- essentially Atriplex julacea and Frankenia palmeri, ing). Cneoridio dumosi–Agavetum shawii is an asso- in sandy soil communities and succulent scrubs. ciation replacing the Inframediterranean Floristic relationships suggest that fruticose vege- Bergerocacto emoryi–Agavetum shawii in the Ther- tation forms a new class Atriplici julaceae–Franke- momediterranean belt. Cneoridium dumosum, a Mar- nietea palmeri. Within the class three new orders may tirense endemic, identified as a component of other be differentiated: Atriplici julaceae–Frankenietalia Thermomediterranean Martirense communities palmeri (alkali scrub), Bergerocacto emoryi–Agave- (Evens and San 2005), is the differential-species of talia shawii (coastal succulent scrub) and Camissonio this new association. Trixido californicae–Stenocer- crassifoliae–Isocometalia menziesii (dune scrub). eetum gummosi is an association physiognomically The new order Atriplici julaceae–Frankenietalia dominated by the large columnar cactus Stenocereus palmeri and its only alliance Atriplici julaceae– gummosus, with erect or more often ascending– Frankenion palmeri correspond to the communities sprawling stems (1–4 m tall) forming thickets 10 m or of the Saltbush Series (Turner and Brown 1982). We more in diameter, that usually lives on rocky hillsides recognize five associations: Atriplici julaceae– and steep well-drained slopes, indicating the most Frankenietum palmeri Peinado et al. 1994 (JULA xeric habitats. clustering less three releve´s moved to ass. 6); The clusterings of the SAND matrix can be Atriplici linearis–Frankenietum palmeri Peinado separated into three large phytosociological com- et al. 2006 (LINE clustering); Encelio phenocodon- plexes: a northern complex of fruticose backdune tae–Atriplicetum polycarpae Peinado et al. 2005 communities (ass. 9–17); a second group comprised (POLY clustering more two releve´s from ALLE); of foredune communities dominated by Abronia Dudleyo cultratae–Lycietum californici (DUDL clus- maritima (ass. 22–26), and a third or Sanlucan tering more six releve´s from ECOT), and Euphorbio complex (ass. 27–37). According to their positions 123 Plant Ecol (2008) 196:27–60 47

Fig. 3 Schematic distribution of the main associations in: (a) bluffs (27°470 N–114°410 W). 1, Sphaeralceo fulvae–Encelie- the Inframediterranean belt of the Martirense province. tum ventori.2,Camissonio crassifoliae–Encelietum ventori. 3, Transect though El Consuelo dunes (30°090 N–115°470 W). Camissonio crassifoliae–Helianthetum nivei. 4, Euphorbio 1, Heliantho nivei–Astragaletum anemophili variant of Astrag- miserae–Lycietum californici. 5, Allenrolfeetum occidentalis. alus anemophilus.2,Heliantho nivei–Astragaletum anemophili 6, Yucco validae–Fouquierietum diguettii. Abbreviations: variant of Isocoma menziesii.3,Ephedro californicae–Lycie- DEFL, deflation areas. HALK, hydroalkaline depression or tum brevipedis.4,Dudleyo cultratae–Lycietum californici.5, alkali sink. WBD, windward backdunes. XALK, xeroalkaline Bergerocacto emoryi–Agavetum shawii.(b) the mesotropical plains belt of the Vizcaıńo sector. Transect though Malarrimo alkali in the psammosere and their dominant biotypes, two ized by a set of psammophilous shrubs and sub- groups may be designated in the Sanlucan complex, shrubs, most of them Martirense and Vizcaıńo backdunes and foredunes; the former (ass. 34–37) endemics (Table 6: taxa of the order II.2 and its formed by phanerophytes with Maytenus phyllantho- alliances). Within this order three well-defined alli- ides shrubs inhabiting windward dunes and sea- ances may be separated: Lycion richii (LYC cluster- exposed rocky slopes with an inmediate influence of ing), Encelion ventori (ENCE and SPHA clusterings), salt spray (ass. 34 and 35), and with thornscrubs in and Heliantho nivei–Isocomion menziesii (VERN, the lee of the innermost dune fringe (ass. 36 and 37). ANEM and NIVE clusterings). In the Sanlucan foredune subgroup (ass. 27–32) The almost exclusive dominance of the intricate phanerophytes are lacking and most species are stems of L. richii (=L. brevipes), that form a thorny perennial herbs and prostrate shrubs. shrubland thriving in primary backdunes in which The fruticose backdune communities of northern there is a more or less direct salt spray influence Baja California (the new order Camissonio crassifo- (Figs. 3a, 4a, b), is the main characteristic of the first liae–Isocometalia menziesii) are perfectly character- alliance. In Mediterranean climate areas Ephedra 123 48 Plant Ecol (2008) 196:27–60 californica is a differential-species of the new between Punta Eugenia and Santa Rosalillita. Sub- association Ephedro californicae–Lycietum richii, strates are alkaline rocks, but are covered by a layer which is replaced in tropical areas by Lycietum of aeolian sands (Fig. 3b). The appearance of the brevipedis Peinado et al. 2005. association changes on the most inclined and windy The alliance Encelion ventori, characterized by the cliff slopes, where shrubs diminish in size becoming small tree Encelia ventorum, includes secondary dune prostrate; S. fulva dominates and E. ventorum even- associations on parabolic dunes and sea bluffs, tually vanishes. endemics of the Vizcaıńo sector and some nearby Heliantho nivei–Isocomion menziesii comprises areas. Within this alliance we recognize two associ- five nanophanerophytic, and chamaephytic associa- ations: Camissonio crassifoliae–Encelietum ventori tions (ass. 9–13) of areas protected from direct salt Peinado et al. 2005 (ENCE clustering), and Sphaer- spray by communities of Lycium richii and/or Encelia alceo fulvae–Encelietum ventori (SPHA clustering), ventorum. Communities belonging to this group show endemic of the wind-battered cliffs of the Inframed- a similar physiognomy. They are generally open iterranean northern half of the El Vizcaıńo peninsula, communities whose major cover is composed of mat-

Fig. 4 Schematic distribution of the main associations in: (a) phoretum mangle and Batido maritimae–Spartinetum foliosae. the Inframediterranean belt of the Vizcaıńo sector. Transect (c) the thermotropical belt of the Sanlucan province. Transect though Guerrero Negro plains, near Laguna Ojo de Liebre though Boca del Salado (23°170 N–109°260 W). 1, Euphorbio (28°020 N–114°010 W). 1, Abronietum maritimae.2,Euphorbio leucophyllae–Drymarietum crassifoliae. 2, Euphorbio leuco- californicae–Lycietum brevipedis. 3, Monanthochloo littoral- phyllae–Jouveetum pilosae.3,Sporobolo virginici–Ipomoetum is–Arthrocnemetum subterminalis (saltmarsh). 4, Camissonio brasiliensis.4,Ipomoeo imperati–Jouveetum pilosae.5,Daleo crassifoliae–Encelietum ventori. 5, Allenrolfeetum occidental- anthonyi–Jouveetum pilosae.6,Lycio congesti–Maytenetum is. 6, Atriplici julaceae–Frankenietum palmeri. (b) the phyllanthoidis.7,Jatropho cordatae–Cyrtocarpetum edulis.8, thermotropical belt of the Magdalenan sector. Transect though Antigono leptopi–Cyrtocarpetum edulis. Abbreviations: BDU, Magdalena Bay sand spit (25°050 N–112°090 W). 1, Abronie- backdunes. DUC, dune crest. FORE, foredunes. HALK, tum maritimae (windward facing foredunes). 2, Sarcostemmato hydroalkaline depression or alkali sink. LBE, lower beach. arenarii-Astragaletum magdalenae (leeward facing foredunes). PBD, primary backdunes. SAL, saltmarsh. SBD, secondary 3, Loto bryanthii-Isocometum menziesii. 4, Lycietum brevipe- backdunes. WDU-1, windward dunes, first level. WDU-2, dis. 5, tidal communities of Lagunculario racemosae–Rhizo- windward dunes, second level. XALK, xeroalkaline plains 123 Plant Ecol (2008) 196:27–60 49 forming subshrubs, with biotypes ranging from cha- facilitating sand sedimentation as a direct result of maephytic, decumbent or prostrate, semiburied by their biomass interference with wind action. The sands on wind-exposed habitats, to nanophanerophy- foredunes of Baja California and Mesoamerica share tic and usually erect in wind-sheltered places. Despite Pantropical and Neotropical taxa; another group of the small size of the aerial parts of the dominants, plants is shared between Baja California and the most of their biomass may be found in their extraor- Xerophytic-Mexican coasts of Sonora and Sinaloa; dinarily developed ligneous root systems, of a much finally, another group of plants penetrates southern greater thickness than the stems. Many of the California: A. maritima, Atriplex leucophylla, Cam- dominants show typical xeropsammophytic features, issonia cheiranthifolia s.l., Chamaecyse micromera such as stems and leaves (usually fleshy) covered with and Croton californicus. These floristic links prompt densely interwoven, generally matted silvery hairs, us to describe the new class Euphorbio leucophyllae– and sunken stomates surrounded by trichomes. In Sporoboletea virginici (Table 6). spring, the yellow colors of the spectacular flowers of When the distribution areas of the dominant the Camissonia species and the heads of Helianthus foredune species of this class are projected on a and Isocoma are most noticeable. map, it can clearly be seen that the area of A. Heliantho nivei–Astragaletum anemophili (ANEM maritima corresponds to the less rainy areas (southern clustering), an endemic association of the Infra- California, north and central Baja California, Sonora Thermomediterranean transitional zone, where it and Sinaloa), while J. pilosa, as occurs in the occupies alkaline sea bluffs and perches on aeolian southern tip of Baja California, replaces A. maritima dunes (Fig. 3a), is physiognomically dominated by as the influence of tropical cyclones and their summer whitish cushions of the character-species Astragalus rains becomes more evident. In the most arid zones, anemophilus, a prostrate chamaephyte that forms both A. maritima and its main associated plants circular clumps, which may attain a diameter of over (Atriplex barclayana, A. leucophylla, A. magdalenae, 1.5 m, emerging from ligneous roots of up to 15 cm Camissonia cheiranthifolia, Sesuvium portulaca- in circumference. The fixing power of these roots strum, Suaeda taxifolia) show all or some of the allows the plant to colonize overhang cliffs (variant traits typical of halophytes: taproots, succulent stems of Astragalus anemophilus) and the herbaceous stems and leaves, and clear signs of salt excretion on leaves of the cushions to retain aeolian sands, forming at sunrise. In contrast, when we look at the dominant hillocks up to 1 m high in wind-sheltered habitats biotypes in the Sanlucan communities, these haloph- behind dune ridges (variant of Isocoma menziesii). ilous features are lacking and the dominant species Camissonio crassifoliae–Helianthetum nivei (NIVE are rhizomatous grasses, hemicryptophytes and cha- clustering less five releve´s removed to Isocomo maephytes that show xerophytic adaptations but not menziesii–Ambrosietum chamissonis) occurs leeward halophytic characters. Hence, from a floristic-ecolog- of aeolian dunes occupied by communities of the ical and biotypic perspective, there are two large associations 14 and 17 (Fig. 3b). Isocomo menziesii– groups of communities, which we treat as orders: Ambrosietum chamissonis colonizes precipitation Abronietalia maritimae for the communities of the ridges and deflation areas leeward of the foredune more arid zones with a predominance of halophytic hillocks created by Atriplici leucophyllae–Abronie- plants, and Sporobolo virginici–Jouveetalia pilosae tum maritimae. Loto bryanthii–Isocometum men- for those of the rainier tropical zones. ziesiii (BRYA clustering) is an association endemic Abronietalia maritimae includes two alliances: of the deflation areas and other wind-sheltered areas Atriplici leucophyllae–Abronion maritimae (Mediter- of the barrier dune complex of the Magdalenan sector ranean) and Palafoxio linearis–Abronion maritimae (Fig. 4b). Finally, the association Heliantho nivei– (Tropical). Besides them, on the entire Gulf coast, Isocometum vernonioidis flourishes on wet interdune pure populations of Sporobolus virginicus appear depressions bordering saltmarshes. here and there (community 33), and seem to occupy Two perennial herbs are the main foredune builder the most seaward zone of the upper beaches or, of the study area: Abronia maritima in a northern sometimes, disturbed places. This suggests a precol- complex (Martirense and Bajacalifornian provinces), onizing role of S. virginicus similar to that of and Jouvea pilosa in the Sanlucan province, both Elytrigia juncea on Europe’s coasts. However, more 123 50 Plant Ecol (2008) 196:27–60 in depth studies and new releve´s are needed before character-species disappear and the strand communi- we can define new syntaxa to group these commu- ties, devoid of J. pilosa, are floristically linked to the nities. alliance Palafoxio linearis–Abronion maritimae. This The foredune vegetation of Mediterranean areas tectonic border has also been described as a place that (18 releve´s from the ABRO clustering) corresponds sees a change in the strand flora (Breckon and to the association Atriplici leucophyllae–Abronietum Barbour 1974) and potential vegetation (Leońdela maritimae Biondi and Cassavechia 2001. Within the Luz et al. 2000). tropical alliance Palafoxio linearis–Abronion mariti- Six new associations can be distingued in the mae, we recognize four associations. Abronietum alliance Oenothero talassaphilae–Jouveion pilosae maritimae Peinado et al. 2005 (bassically the rest of (ass. 27–32). The Sanlucan communities occupying releve´s of the ABRO clustering) corresponds to the the lowest beach stretches in partly stabilized sand foredune vegetation of the Vizcaıńo and Magdalenan away from the immediate shore and subjected to sectors (Figs. 4a, b). Sarcostemmato arenarii–Astra- occasional tidal water floods (Fig. 4c) belong to galetum magdalenae (MAGD clustering) is endemic Euphorbio leucophyllae–Drymarietum crassifoliae of the windiest areas of the Magdalenan sector, (DRYM clustering), characterized by the dominance thriving on the leeward of the foredunes (Fig. 4b). of Drymaria holosteoides var. crassifolia, a prostrate Palafoxio linearis–Daleetum tinctoriae (PALA clus- halophyte with salt excretory glands, and the most tering) is an endemic association of the Angelino- aggressive of the foredune builders in its advance Loretano sector, extended on dunes between Mulege´ toward the sea. The lack of Jouvea pilosa is the and El Cajete, situated just north of the La Paz fault. differential feature of this pioneer association with Finally, Atriplicetum magdalenae, an association respect to the adjacent Euphorbio leucophyllae– dominated by Atriplex magdalenae, appears on the Jouveetum pilosae (21 releve´s from the JOUV upper beaches that show clear signs of anthropozo- clustering), which groups communities of embryonic ogenic activities. dunes formed by D. holosteoides var. crassifolia, E. In contrast to the large, individual conical hillocks leucophylla and J. pilosa on the upper parts of the built by the tap-rooted A. maritima of the north, the Sanlucan beaches. The hollows formed on beaches foredunes of the order Sporobolo virginici–Jouvee- due to the fixing action of embryonic dunes create talia pilosae are covered by the rhizomatous grass wind-sheltered microhabitats, occupied by dense and Jouvea pilosa which forms continuous dune rows prostrate communities of Sporobolo virginici–Ip- appearing as two levels of flat-topped ridges, the first omoeetum brasiliensis (IPOM clustering). usually rising about 1 m above the upper beach and Low-cover communities dominated by Jouvea the second 6–10 m above the first. On the phytogeo- pilosa colonizing the first levels of the flat-topped graphically isolated Sanlucan coasts, this neotropical ridges of the Sanlucan dunes constitutes the Ipomoeo order is represented by the endemic alliance Oenot- imperati–Jouveetum pilosae (29 releve´s from the hero talassaphilae–Jouveion pilosae characterized by JOUV clustering). Daleo anthonyi–Jouveetum pilo- several Sanlucan endemics (see Table 6) and by sae (22 releve´s from the JOUV clustering) includes strand species (Froelichia interrupta, Houstonia dune shrub communities of dense cover co-domi- mucronata, Jouvea pilosa, Ipomoea costellata, I. nated by J. pilosa colonizing the second levels of the imperati, I. pes-caprae subsp. brasiliensis, Portulaca flat-topped ridges of the Sanlucan dunes. Dalea pilosa and Scaevola plumieri) whose northern limits divaricata subsp. anthonyi is characteristic of this in Baja California are at, or south of 24° N, i.e., the association and extends along the entire coast of the Sanlucan province. The boundary line (La Paz fault) Sanlucan province, except for the western side of separating the Cape sediments of granite origin from northern Bahıá La Paz, between Pichilinguë and the basalt derived sediments of the northern areas can Bahıá Balandra, where it is replaced by Daleo be used as an easily identifiable landscape trait to maritimae–Jouveetum pilosae (7 releve´s from the delineate communities of Oenothero talassaphilae– JOUV clustering). Jouveion pilosae. Immediately north of the tectonic Maytenus phyllanthoides dominates three shrub- fault, in Todos Santos on the Pacific coast and in land associations (MAY1 clustering less three rele- Bahıá La Paz on the Gulf coast, the alliance ve´s; ass. 34–36). Besides one already described 123 Plant Ecol (2008) 196:27–60 51

(Maytenetum phyllanthoidis Peinado et al. 1995), in phytic-Mexican deserts are extraordinarily marked the Sanlucan province M. phyllanthoides dominates and are based on ecophysiological differences (Lud- two backdune associations: Cyrtocarpo edulis–May- wig et al. 1988). In order to distinguish them, Knapp tenetum phyllanthoidis thriving on the leeward of the (1957) proposed the classes Amarantho–Boerhaavie- backdunes whose windward slopes are occupied by tea (summer-annuals) and Chorizantho–Nametea dense and flagged communities of Lycio congesti– (winter-annuals), both invalidly published. The win- Maytenetum phyllanthoidis. The sandy inland plains ter-annual communities of the Xerohytic–Mexican immediately behind those dune systems are inhabited region are included here in the new class Achyron- by columnar cacti and many deciduous small trees ichio cooperi–Abronietea villosae. that have fleshy stems of swollen appearance (sarco- The new association Amblyopappo pusilli–Mese- caulescent, see Shreve and Wiggins 1964). These mbryanthemetum crystallini (AMBL clustering) ap- sarcocaulescent thornscrubs growing on arenosols pears in two habitats. The first (typical variant) is form the association Jatropho cordatae–Cyrtocarpe- formed by the sunny spaces between shrubs of the tum edulis, which is floristically related to the associations 7 and 19. In these sites, the succulent regional climax of the association Antigono leptopi– biotypes and red colors of two introduced iceplants, Cyrtocarpetum edulis, inhabiting regosols (Peinado Mesembryanthemum nodiflorum and M. crystallinum, et al. 1995d), and also belonging to the class predominate visually. The second microhabitat com- Pachycereo pecten-aborigini–Lysilometea divarica- prises the shady areas under the shrub canopy, mainly tae. on northern exposures. In these microhabitats, whose The YUCC group corresponds to the Vizcainoan areas are but a few cm2, the iceplant cover diminishes association Yucco validae–Fouquierietum diguetii and even disappears, and the dominance is taken over Peinado et al. 1995. The high presence of Larrea by A. pusillus and Pterostegia drymarioides. tridentata in this group, as well as in the ERRA group The communities of disturbed habitats of western (corresponding to the Sanfelipense association Erra- North America share many introduced species with zurizio megacarpae–Ephedretum trifurcae Peinado the cosmopolitan class Stellarietea mediae (Heady et al. 2006) relates both associations to the Xero- 1988; Sawyer and Keeler-Wolf 1995). This has phytic-Mexican class Prosopido torreyanae–Fouqui- already been indicated for the communities of erietea splendentis Rivas-Martıńez 1997, of which L. Brometalia rubenti-tectori (Peinado et al. 1995e). tridentata is a character-species. Rivas-Martıńez et al. (1993) described the alliance The winter-annual communities of the Vizcaıńo Mesembryanthemion crystallini (Chenopodietalia sector are included in the new association Plantagini muralis) to group communities of prostrate and ovatae–Chaenactidetum lacerae (CHAE clustering). succulent therophytes of the genus Mesembryanthe- This association appears in the gaps between the mum thriving after winter rains in the arid and shrubs of the associations 5 and 6. It also appears in semiarid zones of the Inframediterranean and Ther- deflation areas and on secondary backdunes, in momediterranean belts of southern Europe, Northern clearings of the associations 12, 14 and 15. After Africa and Canary Islands. Two of the characteristic the last winter rains, the biomass of the dominants is members of the alliance, M. crystallinum and M. impressive and the red stems and pinkish white heads nodiflorum, are the dominant plants of the association of Chaenactis lacera (up to 50 cm tall) dominate the Amblyopappo pusilli–Mesembryanthemetum crystal- landscape of the alkali-sandy plains of El Vizcaıńo, lini along with Amblyopappus pusillus, a pan-Amer- surpassing the height of the shrubby vegetation and ican element, whose distribution area in western visually dominating it. In heavy soils of clayish North America is restricted to the Inframediterranean texture Dyssodia anthemidifolia tends to dominate. In and Thermomediterranean belts of southern Califor- disturbed areas and tilled land, the spectacular growth nia and Baja California; it is a self-fertile, autoga- of Mesembryanthemum crystallinum occurs and is mous plant which is presumably dispersed by accompanied by a clear loss of biomass correspond- migratory birds (Raven 1963). The habitats of this ing to the dominants. association are coastline zones that show evident Floristic differences between communities of signs of animal activity, mainly of birds, reptiles and winter-annuals and summer-annuals in the Xero- small mammals, i.e., on disturbed places similar to 123 52 Plant Ecol (2008) 196:27–60 those occupied by other communities of Mesembr- Costa (24°220 N–110°410 W); 35, El Junco (24°240 yanthemion crystallini. N–110°410 W); 36, Puerto Chale (24°250 N–110° 320 W); 37, Punta Tarabillas (24°260 N–110°410 W); Acknowledgments This study was made possible by an 38, Puerto Cancun (24°350 N–111°410 W); 39, Las ´ agreement between the Universidad de Alcala and Universidad A´ nimas (24°370 N–110°440 W); 40, Punta Coyote Autońoma de Baja California, and supported by grants from 0 0 the Direccioń General de Universidades (PR2004-0176) and (24°41 N–110°43 W); 41, Puerto San Carlos Agencia Espanõla de Cooperacioń Internacional (A/5197/06). (24°470 N–112°070 W); 42, Isla Magdalena We are grateful for the constructive comments by three (25°050 N–112°090 W); 43, Isla Magdalena anoymous reviewers and especially by the co-ordinating editor (25°120 N–112°070 W); 44, Puerto Abelardo Lo´pez Erwin Bergmeier. Part of this research was carried out during a 0 0 stay at the Facultad de Ciencias de la Universidad Autońoma Mateos (25°13 N–112°07 W); 45, Isla de Santo de Baja California en Ensenada. The authors thank the faculty Domingo (25°170 N–112°070 W); 46, El Paraı´so head, Dr. Nahara Ayala, for supporting our fieldwork. We also (25°350 N–112°030 W); 47, Estero el Gato thank Ana Burton for help with the English translation. (25°390 N–112°030 W); 48, La Poza Grande (25°410 N–112°040 W); 49, Laguna Puerto Escondido (25°490 N–111°170 W); 50, Loreto (26°000 N– Appendix 1: Sites sampled (see Fig. 1) 111°210 W); 51, San Juanico (26°150 N–112°270 W); 52,ElDa´til (26°260 N–112°470 W); 53,Bahıá 1, Migrinõ (23°020 N–110°060 W); 2, Bahıá Tortuga Concepcioń (26°330 N–111°430 W); 54,Bahıá Con- (23°060 N–109°320 W); 3, La Fortuna (23°080 N– cepcioń (26°340 N–111°400 W); 55, Bahıá Concep- 109°300 W); 4, Santa Elena (23°090N–109°290 W); 5, cioń (26°430 N–111°530 W); 56, Bahıá de Ballenas Punta Paredones (23°100 N–109°280 W); 6, Boca de (26°440 N–113°320 W); 57, Playa del Burro la Vinorama (23°130 N–109°270 W); 7, Plutarco (26°440 N–111°530 W); 58, Playa Santispac Elıás Calles (23°140°N–110°090W); 8, Boca de la (26°460 N–111°530 W); 59, between Punta Abreojos Ardilla (23°150 N–109°260 W); 9, Boca del Salado and El Coyote (26°470 N–113°300 W); 60, Playa los (23°170 N–109°260 W); 10, Playa Los Cerritos Naranjos (26°470 N–111°510 W); 61, La Bocana, El (23°180 N–110°090 W); 11, El Pescadero Vizcaıńo Biosphere Reserve (26°490 N–113°430 W); (23°190 N–110°100 W); 12, Playa San Pedrito, Bahıá 62, Mulege´ dunes (26°520 N–111°550 W); 63,Bahıá de Todos Santos (23°210 N–110°110 W); 13,Bahıá de San Hipo´lito (26°520 N–113°450 W); 64,El de los Frailes (23°220 N–109°250 W); 14, Parque Vizcaıńo Biosphere Reserve (26°560 N–113°480 W); Nacional Cabo Pulmo (23°260 N–109°250 W); 15, 65, La Serenidad, Mulege´ (26°560 N–112°020 W); 66, Cabo Pulmo (23°270 N–109°260 W); 16, Las Play- Punta Prieta (27°010 N–114°010 W); 67, Punta Chi- itas, Todos Santos (23°290 N–110°160 W); 17, Punta vato (27°040 N–111°570 W); 68, Bahıá Abreojos road Las Arenas lighthouse (23°330 N–109°290 W); 18, (27°070 N–114°070 W); 69, Playa Los Me´danos Punta Colorada (23°330 N–109°300 W); 19,La (27°080 N–114°120 W); 70, Bahıá Asuncioń Ribera (23°350 N–109°320 W); 20, Mocorito, Bahıá (27°090 N–114°180 W); 71, Rancho El Paraı´so las Palmas (23°360 N–109°340W); 21, Ejido La (27°110 N–113°170 W); 72, Barra de San Bruno Conquista (23°560N–110°510W); 22, Las Arenas (27°120 N–112°110 W); 73, Bahıá Tortugas (23°590N–109°490 W); 23, El Teso, Bahıá la Ven- (27°410 N–114°530 W); 74, Punta Caballo de Piedra, tana (24°040 N–109°560 W); 24, Punta Conejo Malarrimo (27°470 N–114°420 W); 75, Estero Laguna (24°040 N–111°010 W); 25, El Sargento (24°050 Ojo de Liebre (27°470 N–114°050 W); 76, Malarrimo N–110°000 W); 26, Bahıá Ventana (24°080 N– (27°460 N–114°340 W); 77, El Chevo (27°490 109°580 W); 27, El Cajete (24°140 N–110°360 W); N–114°510 W); 78, Laguna Ojo de Liebre (27°520 28, between La Paz and Pichilinguë (24°150 N– N–113°590 W); 79, Guerrero Negro (27°570 N–114°040 110°180 W); 29, Bahıá Pichilingue (24°170 N–110° W); 80, Guerrero Negro (28°020 N–114°010 W); 81, 200 W); 30,Bahıá Balandra (24°190 N–110°190 W); Jesu´s y Marıá (28°060 N–114°000 W); 82, La Bocana 31, Playa El Tecolote (24°200 N–110°180 W); 32,El de Jesu´s y Marıá (28°130 N–114°030 W); 83, Laguna Camaroń (24°200 N–110°390 W); 33, Rancho Piedras Manuela (28°150 N–114°040 W); 84, Miller0s Landing Coloradas (24°210 N–110°400 W); 34, San Juan de la (28°290 N–114°030 W); 85, trail between Rosarito and

123 Plant Ecol (2008) 196:27–60 53

San Borja (28°390 N–113°590 W); 86, Santa Rosalil- Appendix 2: Distribution of taxa by lita (28°410 N–114°140 W); 87, Isla Cedros (28°130 phytogeographical elements N–115°130 W); 88, Bahıá de los A´ ngeles (28°550 N–113°330 W); 89, trail between San Borja and Bahıá Californian (CAL): Aphanisma blitoides, Artemisia Los A´ ngeles (28°580 N–113°390 W); 90, Punta Canoas californica, Astragalus trichopodus, Atriplex leuco- (29°260 N–115°120 W); 91, Puerto Catarina phylla, Calystegia macrostegia subsp. tenuifolia, (29°310 N–115°150 W); 92, Punta San Carlos Cistanthe maritima, Eriodictyon crassifolium, Eri- (29°370 N–115°310 W); 93, Punta Baja (29°580 ogonum fasciculatum var. fasciculatum, Galium an- N–115°470 W); 94, Bocana del Rosario (30°020 gustifolium subsp. angustifolium, Hemizonia N–115°470 W); 95, duna El Consuelo (30°090 fasciculata, Hordeum intercedens, Isocoma menziesii N–115°470 W); 96, El Campito (30°090 N–115°480 var. vernonioides, Lotus hamatus, L. scoparius var. W); 97, Rancho El Tranquilo (30°160 N–115°480 W); scoparius, Malacothamnus fasciculatus, Malosma 98, El Socorrito (30°190 N–115°490 W); 99, Puente laurina, Nassella lepida, Pentagramma triangularis Arroyo Hondo (30°210 N–115°490 W); 100,El subsp. viscosa, Rhamnus crocea, Rhus integrifolia, Pabelloń, bahıá de Santa Marıá (30°220 N–115°510 Ribes speciosum, Sairocarpus nuttallianus, Suaeda W); 101, San Quintıń (30°240 N–115°540 W); 102, esteroa. Holarctic (HOL): Oligomeris linifolia. Arroyo San Simoń (30°260 N–115°520 W); 103, Los Introduced (INT): Atriplex semibaccata, Avena Volcanes (30°270 N–116°020 W); 104, El Papolote barbata, Bromus rubens, Cakile maritima, Carpobro- (30°270 N–115°470 W); 105, La Chorera (30°280 tus chilensis, Crassula tillaea, Erodium cicutarium N–116°020 W); 106, La Pedrera (30°290 N–116°030 subsp. cicutarium, Hordeum murinum subsp. lepori- W); 107, Campo Cimarroń, Puertecitos (30°250 num, Lamarckia aurea, Malva parviflora, Medicago N–114°380 W); 108, Laguna Figueroa (30°410 polymorpha, Melilotus indica, Mesembryanthemum N–116°010 W); 109, Rancho Las Palmas, between crystallinum, M. nodiflorum, Nicotiana glauca, Poa San Felipe and Puertecitos (30°460 N–114°430 W); annua, Polypogon monspeliensis, Salsola tragus, 110, Bahıá Camalu´ (30°470 N–116°050 W); 111, San Schismus barbatus, Sonchus oleraceus, S. tenerrimus, Felipe (30°570 N–114°470 W); 112,Bahıá Colonet Spergularia bocconii, Tamarix ramosissima. Madre- (30°580 N–116°170 W); 113, between Ejido Dıáz an (MAD): Abronia maritima, A. umbellata subsp. Ordaz and Rancho Meeling (30°580 N–116°070 W); umbellata, Acalypha californica, Allium haematochi- 114, San Telmo (31°050 N–116°110 W); 115, Ejido ton, Ambrosia chenopodifolia, Arthrocnemum subter- Alfredo B. Bonfil (31°070 N–116°070 W); 116, San minale, Atriplex julacea, Baccharis sarothroides, Antonio del Mar (31°070 N–116°190 W); 117, Bocana Bromus arizonicus, Cleome isomeris, Croton califor- Ereńdira (31°160 N–116°230 W); 118, Puerto San nicus, Cryptantha maritima var. maritima, Dic- Isidro (31°170 N–116°240 W); 119, Punta Cabras helostemma capitatum subsp. pauciflorum, Dudleya (31°190 N–116°270 W); 120, La Bocana de Santo lanceolata, D. pulverulenta subsp. pulverulenta, Toma´s (31°330 N–116°410 W); 121, Coronel Esteban Echinocereus maritimus, Encelia californica var. Cantu´ (31°370 N–116°400 W); 122, Punta Banda californica, Ephedra californica, Euphorbia misera, (31°430 N–116°430 W); 123, La Salina, Ensenada Ferocactus cylindraceus var. cylindraceus, Frankenia (31°490 N–116°360 W); 124, Bahıá de Todos los palmeri, Helianthus niveus subsp. niveus, Isocoma Santos (31°520 N–116°370 W); 125, San Miguel menziesii var. menziesii, Lepidium nitidum, Lotus (31°530 N–116°450 W); 126, Playa Saldamando rigidus, Lupinus concinnus, Lycium andersonii var. (31°560 N–116°460 W); 127, Salsipuedes (31°580 andersonii, L. californicum, L. richii, Mammillaria N–116°470 W); 128, La Salina, sur de Tijuana dioica, Marah macrocarpus, Melica frutescens, Mir- (32°030 N–116°540 W); 129, Plaza del Mar abilis californica var. californica, Nemacaulis denu- (32°070 N–116°550 W); 130,ElMe´dano (32°130 data, Nolina parryi, Opuntia ganderi var. ganderi, N–116°540 W); 131,ElRosarito(32°170 N–117°030 W); Plantago ovata, Porophyllum gracile, Prosopis glan- 132, Tijuana Estuary (32°340 N–117°080 W). dulosa var. torreyana, Ribes tortuosum, Simmondsia

123 54 Plant Ecol (2008) 196:27–60 chinensis, Sphaeralcea ambigua, Stillingia linearifo- Atriplex barclayana subsp. barclayana, A. barclayana lia, Suaeda taxifolia, Trixis californica, Viguiera subsp. sonorae, A. canescens subsp. linearis, Brande- laciniata. Magdalenan (MGD): Cynanchum penin- gea bigelovii, Bursera fagaroides var. elongata, B. sulare, Dalea brandegeei. Martirense (MAR): Achn- hindsiana, B. microphylla, Calliandra eriophylla var. atherum diegoense, Aesculus parryi, Agave shawii eriophylla, Cenchrus palmeri, Condalia globosa var. subsp. shawii, Astragalus anemophilus, Bergerocac- pubescens, Condaliopsis lycioides var. canescens, tus emoryi, Camissonia cheiranthifolia subsp. suffr- Coreocarpus parthenoides var. parthenoides, Cras- uticosa, Cneoridium dumosum, Dudleya attenuata sula connata var. eremica, Dalea mollis subsp. mollis, subsp. orcuttii, D. cultrata, Eriogonum fastigiatum, E. Echinocereus engelmannii var. engelmannii, Encelia scalare, Ferocactus viridescens, Haplopappus ber- farinosa var. farinosa, E. farinosa var. phenocodonta, beridis, H. rosaricus, Opuntia littoralis, O. prolifera, E. frutescens var. frutescens, E. halimifolia, Ephedra Rosa minutifolia, Salvia munzii, Selaginella cineras- aspera, E. trifurca, Eriogonum fasciculatum var. cens. Neotropical (NEO): Cardiospermum corindum, flavoviride, Euphorbia californica var. californica, Chamaesyce micromera, Froelichia interrupta, Ip- E. leucophylla, Fagonia pachyacantha, Fouquieria omoea costellata, I. imperati, I. pes-caprae subsp. diguetii, Haplopappus sonorensis, Hibiscus denuda- brasiliensis, Jatropha cinerea, Jouvea pilosa, Larrea tus, Horsfordia alata, H. newberryi, Idria columnaris, tridentata var. tridentata, Lycium carolinianum, Jatropha cuneata, Justicia californica, Krameria Maytenus phyllantoides, Passiflora foetida var. long- erecta, K. paucifolia, Lycium berlandieri var. penin- ipedunculata, Phaseolus acutifolius var. latifolius, sulare, L. exsertum, L. fremontii var. congestum, Portulaca pilosa, Sapindus saponaria, Selaginella Olneya tesota, Opuntia echinocarpa var. echinocar- lepidophylla, Sporobolus virginicus, Stegnosperma pa, O. ramosissima, Pachycereus pringlei, P. schottii halimifolium. North American (NOA): Atriplex var. schottti, Palafoxia linearis, Parkinsonia micro- canescens subsp. canescens, A. polycarpa, Commeli- phylla, Pedilanthus macrocarpus, Peucephyllum na diffusa, Distichlis spicata, Monanthochloe litto- schottii, Phoradendron californicum, Phrygilanthus ralis, Polycarpon depressum, Sarcocornia pacifica, sonorae, Physalis crassifolia var. crassifolia, Pithe- Vulpia octoflora var. hirtella. North American– cellobium mexicanum, Pleuraphis rigida, Probosci- South American (NAS): Amblyopappus pusillus, dea althaefolia, Prosopis velutina, Pseudorontium Ambrosia chamissonis, Atamisquea emarginata, Batis cyathiferum, Ruellia californica, Solanum hindsia- maritima, Cardionema ramosissimum, Frankenia num, Stenocereus gummosus, Stephanomeria paucifl- salina, Heliotropium curassavicum var. oculatum, ora, Tiquilia plicata, Triteleiopsis palmeri, Viguiera Muhlenbergia microsperma, Perityle emoryi, Sesuvium deltoidea var. parishii, V. parishii, Wislizenia refracta portulacastrum, Tillandsia recurvata. Pantropical var. mammillata. Tropical Bajacalifornian (BAJ): (PAN): Macroptilium atropurpureum, Malvastrum Acacia brandegeana, A. peninsularis, Aeschynomene coromendalianum, Momordica charanthia, Scaveola nivea, Agave datylio var. vexans, A. shawii subsp. plumieri. Sanlucan (SAN): Abutilon xanti, Bursera goldmaniana, Ambrosia bryanthii, A. magdalenae, cerasifolia, B. epinnata, B. filicifolia, Caesalpinia Argythamnia brandegeei var. intonsa, Astragalus placida, Condaliopsis rigida, Coulterella capitata, fastidius, Atriplex barclayana subsp. lurida, A. mag- Cyrtocarpa edulis, Dalea divaricata subsp. anthonyi, dalenae, Bebbia juncea var. juncea, Camissonia D. maritima, Drymaria holosteoides var. crassifolia, cardiophylla subsp. cedrosensis, Cassia confinis, Encelia farinosa var. radians, Euphorbia xantii, Castela peninsularis, Cuscuta veatchii, Dalea tincto- Jatropha cordata, Lemaireocereus thurberi var. litto- ria var. tinctoria, Dithyrea californica var. clinata, ralis, Mammillaria capensis, Oenothera drummondii Dudleya ingens, Dyssodia anthemidifolia, D. speci- var. thalassaphila, Perityle crassifolia var. crassifo- osa, Echinocereus brandegeei, Echinopepon minimus, lia, Porophyllum porphyreum. Sonoran: Achyrony- Encelia californica var. asperifolia, E. palmeri, chia cooperi, Allenrolfea occidentalis, Amaranthus Errazurizia benthamii, E. megacarpa, Euphorbia watsonii, Ambrosia camphorata, A. dumosa, Antigo- polycarpa var. johnstonii, Ferocactus towsendianus, non leptopus, Argythamnia serrata, Asclepias albi- Harfordia macroptera, Houstonia mucronata, Hyptis cans, A. subulata, Astragalus magdalenae var. laniflora, Ibervillea sonorae var. peninsularis, Isoco- magdalenae, A. nuttallianus var. cedrodensis, ma menziesii var. tridentata, Lotus bryantii, Lycium 123 Plant Ecol (2008) 196:27–60 55 megacarpum, Mammillaria albicans, M. hutchinson- nom. inval. Art. 8 ICPN). Holotypus: Allenrolfeion iana, Myrtillocactus cochal, Nicolletia trifida, Opun- occidentalis alliancia nova. tia alcahes, O. cholla, O. ciribe, O. invicta, Allenrolfeetea occidentalis Knapp classis nova hoc O. lyndsayi, O. molesta, O. rosarica, O. tesajo, loco (Allenrolfeetea occidentalis Knapp 1957 nom. Physalis glabra, Pithecellobium confine, Porophyllum inval. Art. 8 ICPN). Holotypus: Allenrolfeetalia maritimum, Prosopis palmeri, Sarcostemma arenari- occidentalis Knapp ordo novus. um, Viguiera deltoidea var. chenopodina, Viscainoa Allenrolfeion occidentalis alliancia nova hoc loco. geniculata var. geniculata. Vizcaıńo (VIZ): Agave Holotypus: Allenrolfeetum occidentalis Peinado et al. shawii subsp. sebastiana, Astragalus harbisonii, 1994. Camissonia crassifolia, Chaenactis lacera, Encelia Allenrolfeo occidentalis–Maytenetum phyllanthoi- laciniata, E. ventorum, Eriogonum encelioides, Fero- dis associatio nova hoc loco. NTR: Reg. 3505, site cactus acanthodes var. tortulospinus, F. fordii var. 54, 03/23/2005, 0 msl, W, 100 m2, 100%, 1 m. fordii, F. gracilis var. coloratus, F. gracilis var. Physiognomy and habitat: Maytenus phyllanthoides gracilis, Lotus distichus, Mammillaria brandegeei, shrubs on wet alkali flats. Biogeo.: IIb. Biocl.: Tt, Ar, Pachycormus discolor var. veatchiana, Sphaeralcea Eo. Floristic combination S1 (meso- and nano- fulva, Viguiera lanata, V. microphylla, Yucca valida. phanerophytic): Maytenus phyllanthoides 4, Lycium Western North American (WES): Hordeum depres- exsertum 2. S2 (nanophanerophytic to chamaephytic): sum, Pterostegia drymarioides, Suaeda nigra. Allenrolfea occidentalis 2. Amblyopappo pusilli–Mesembryanthemetum crystallini associatio nova hoc loco. NTR: Reg. 1197, Appendix 3: Nomenclatural statement site 97, 03/23/1997, 25 msl, 10 m2, 80%, 0.05 m. Physiognomy and habitat: Therophytic pasture In this appendix we have arranged, in alphabetical growing on an alkali plain close to a cattle track. order, nomenclatural types and diagnoses (or refer- Potential vegetation: Dudleyo cultratae–Lycietum ences to published diagnoses) for syntaxa in need of californici. Biogeo.: Ib. Biocl.: Im, Arid, Ho. typification (Weber et al. 2000). Diagnoses are Floristic combination: Mesembryanthemum crystall- completed by the descriptions made in the previous inum 4, Amblyopappus pusillus 3, Mesembryanthe- sections, especially in Tables 4–6. Nomenclatural mum nodiflorum 1, Crassula connata var. eremica 1, type releve´s (NTR) of new associations include: A. julacea+. registration number (Peinado´s North American Phy- Atriplicetum magdalenae associatio nova hoc tosociological Databank), site number as in Appendix loco. NTR: Reg. 1205, site 68, 03/21/2005, 0 msl, 2, date, plot altitude (msl), plot exposure, plot surface W, 100 m2, 20%, 0.4 m. Physiognomy and habitat: area (m2), vegetation cover (%), average vegetation Herbaceous vegetation on beaches, bordering the height (m) and ecological, physiognomic (S1: dom- debris line. Biogeo.: IIa. Biocl.: Tt, Ar, Ho. inant stratum; S2 subordinate strata), biogeographical Floristic combination S1 (therophytic): Atriplex (Biog.: as in Fig. 1) and bioclimatic (Biocl.) sketches. magdalenae 2. S2 (nanophanerophytic, chamaephy- Bioclimatic abbreviations as in Table 4, more Eo tic and prostrate perennial): Atriplex canescens (Euoceanic) and Ho (Hyperoceanic). subsp. canescens 1, Abronia maritima 1, Frankenia Abronietalia maritimae Knapp ordo novus hoc palmeri+. loco (Abronietalia maritimae Knapp 1957 nom. inval. Atriplici julaceae–Frankenietalia palmeri ordo Art. 8 ICPN). Holotypus: Atriplici leucophyllae– novus hoc loco. Holotypus: Atriplici julaceae– Abronion maritimae alliancia nova. Frankenion palmeri alliancia nova. Achyronichio cooperi–Abronietea villosae classis Atriplici julaceae–Frankenietea palmeri classis nova hoc loco (Chorizantho–Nametea Knapp 1957 nova hoc loco. Holotypus: Atriplici julaceae–Franke- nom. inval. Art. 8 ICPN). Holotypus: Nicolletio nietalia palmeri ordo novus. trifidae–Verbenetalia bajacalifornicae ordo novus. Atriplici julaceae–Frankenion palmeri alliancia Allenrolfeetalia occidentalis Knapp ordo novus nova hoc loco. Holotypus: Atriplici julaceae–Franke- hoc loco (Allenrolfeetalia occidentalis Knapp 1957 nietum palmeri Peinado et al. 1994.

123 56 Plant Ecol (2008) 196:27–60

Atriplici leucophyllae–Abronion maritimae allian- scidea althaefolia 1, Froelichia interrupta 1, Phase- cia nova hoc loco. Holotypus: Atriplici leucophyllae– olus acutifolius var. latifolius 1, Portulaca pilosa+. Abronietum maritimae Biondi and Cassavechia 2001. Daleo maritimae–Jouveetum pilosae associatio nova Bergerocacto emoryi–Agavetalia shawii ordo no- hoc loco. NTR: Reg. 7005, site 30, 03/26/2005, 5 msl, vus hoc loco. Holotypus: Agavion shawii Rivas- W, 50 m2, 70%, 0.3 m. Physiognomy and habitat: Dense Martıńez 1997. community of Jouvea pilosa and Dalea maritima,onthe Camissonio crassifoliae–Helianthetum nivei asso- upper slope of a continuous foredune. Biogeo.: III. ciatio nova hoc loco. NTR: Reg. 10397, site 98, 03/ Biocl.: Tt, Ar, Ho. Floristic combination: S1 (rhizoma- 28/1997, 35 msl, SE, 100 m2, 50%, 0.4 m. Physiog- tous grasses and scattered scrubs, nanophanerophytes): nomy and habitat: Prostrate dune-scrub growing in J. pilosa 3, D. maritima 1, S2 (scattered herbs on gaps): aeolian deflation areas, leeward of dune ridges with Atriplex magdalenae 1, Proboscidea althaefolia 1, Ephedro californicae–Lycietum richii. Biogeo.: Ib. Froelichia interrupta 1, Palafoxia linearis 1, Wislizenia Biocl.: Tm, Arid, Ho. Floristic combination S1 refracta var. mammillata 1. (chamaephytic–nanophanerophytic): Isocoma menzi- Dudleyo cultratae–Lycietum californici associatio esii var. menziesii 2, Helianthus niveus subsp. niveus nova hoc loco. NTR: Reg. 1404, site 106, 04/03/2004, 1, Opuntia prolifera 1, Ephedra californica+. S2 25 msl, WSW, 100 m2, 70%, 0.8 m. Physiognomy and (prostrate perennial): Camissonia crassifolia 1. habitat: Dune scrub perched on alkali cliffs. Biogeo.: Camissonio crassifoliae–Isocometalia menziesii Ib. Biocl.: Im, semiarid, hyperoceanic. Floristic com- ordo novus hoc loco. Holotypus: Heliantho nivei– bination: S1 (meso- and nano-phanerophytic): Lycium Isocomion menziesii alliancia nova. californicum 3, Euphorbia misera 2, Pachycereus Chaenactido lacerae–Dyssodion anthemidifoliae schottii var. schottii 1, Haplopappus berberidis+. S2 alliancia nova hoc loco. Holotypus: Plantagini (chamaephytic): Atriplex julacea 2, Mirabilis califor- ovatae–Chaenactidetum lacerae associatio nova. nica var. californica 2, Dudleya cultrata 1. S2 Cneoridio dumosi–Agavetum shawii associatio (climbing geophyte): Marah macrocarpus 1. S2 (win- nova hoc loco. NTR: Reg. 1389, site 121, 02/17/ ter-therophytes): Mesembryanthemum crystallinum 2, 1989, 100 msl, S, 100 m2, 60%, 0.7 m. Physiognomy Abronia umbellata subsp. umbellata 2, Cryptantha and habitat: Costal succulent scrub on basalts. maritima var. maritima 1, Nemacaulis denudata 1. Biogeo.: Ia. Biocl.: Tm, Sa, Ho. Floristic combination Encelion ventori alliancia nova hoc loco. Holoty- S1 (nanophanerophytic scrubs and succulents): Sim- pus: Camissonio crassifoliae–Encelietum ventori mondsia chinensis 2, Bergerocactus emoryi 2, Vigui- Peinado et al. 2005. era laciniata 2, Artemisia californica 2, Agave shawii Ephedro californicae–Lycietum richii (Peinado subsp. shawii 1, Euphorbia misera 1, Lycium cali- et al. 2005) associatio nova hoc loco. Holotypus: fornicum 1, Ephedra californica+. S2 (chamaephytic Lycietum brevipedis ephedretosum californicae Pei- scrubs and succulents): Cneoridium dumosum 2, nado et al. 2005. Ambrosia chenopodifolia 1, Eriogonum fasciculatum Euphorbio leucophyllae–Drymarietum crassifoliae var. fasciculatum 1, Dudleya attenuata subsp. orcuttii associatio nova hoc loco. NTR: Reg. 10905, site 18, 1, Acalypha californica 1, Mammillaria dioica+. S2 03/27/2005, 0 msl, NE, 20 m2, 60%, 0.05 m. (herbs): Selaginella cinerascens 1. Physiognomy and habitat: Pioneer vegetation on Daleo anthonyi–Jouveetum pilosae associatio beaches forming semi-buried small mounds along nova hoc loco. NTR: Reg. 12505, site 15, 03/28/ the tidal line. Biogeo.: III. Biocl.: Tt, Ar, Ho. Floristic 2005, 5 msl, NE, 100 m2, 60%, 0.3 m. Physiognomy combination: Drymaria holosteoides var. crassifolia and habitat: Dense community of Jouvea pilosa and 3, Euphorbia leucophylla 2, Oenothera drummondii Dalea divaricata subsp. anthonyi, on the upper slope var. talassaphila 1. of a continuous foredune. Biogeo.: III. Biocl.: Tt, Ar, Euphorbio leucophyllae–Jouveetum pilosae asso- Ho. Floristic combination: S1 (rhizomatous grasses ciatio nova hoc loco. NTR: Reg. 10605, site 18, 03/ and scattered scrubs, nanophanerophytes): J. pilosa 3, 27/2005, 0 msl, NE, 2 m2, 60%, 0.1 m. Physiognomy D. divaricata subsp. anthonyi 1, Asclepias subulata 2. and habitat: Pioneer vegetation on the upper part of S2 (scattered herbs on gaps): Oenothera drummondii the beach, forming small hillocks. Biogeo.: III. var. talassaphila 2, Euphorbia leucophylla 1, Probo- Biocl.: Tt, Ar, Ho. Floristic combination: S1 (rhizo- 123 Plant Ecol (2008) 196:27–60 57 matous grasses): Jouvea pilosa 3. S2 (scattered herbs Oenothera drummondii var. talassaphila 2, Euphor- on gaps): Drymaria holosteoides var. crassifolia 1, bia leucophylla 1, Proboscidea althaefolia 1, Ip- Euphorbia leucophylla 1. omoea pes-caprae subsp. brasiliensis+, Palafoxia Euphorbio leucophyllae–Sporoboletea virginici linearis+. classis nova hoc loco. Holotypus: Sporobolo virgin- Isocomo menziesii–Ambrosietum chamissonis as- ici–Jouveetalia pilosae ordo novus. sociatio nova hoc loco. NTR: Reg. 1289, site 129, Euphorbio miserae–Lycietum californici associa- 02/14/1989, 5 msl, W, 10 m2, 100%, 0.4 m. tio nova hoc loco. NTR: Reg. 3904, site 61, 04/06/ Physiognomy and habitat: Dune-scrubs on semi- 2004, 15 msl, WSW, 100 m2, 50%, 0.8 m. Physiog- fixed dunes. Biogeo.: Ia. Biocl.: Tm, Sa, Ho. nomy and habitat: Open scrub on windy alkali plains Floristic combination: S1 (chamaephytic to nano- (calcaric regosols). Biogeo.: IIa. Biocl.: Tt, Ha, Ho. phanerophytic): Ambrosia chamissonis 4, Croton Floristic combination S1 (meso- and nano-phanero- californicus 3, Isocoma menziesii var. menziesii 1, phytic): Lycium californicum,2,Fouquieria diguetii Helianthus niveus subsp. niveus 1. S2 (prostrate 2, Euphorbia misera 1, Encelia farinosa var. pheno- subshrubs): Carpobrotus chilensis 2, Camissonia codonta,1,Ferocactus acanthodes var. tortulospi- cheiranthifolia subsp. suffruticosa 1. S2 (herbs): nus+, Opuntia prolifera+. S2 (chamaephytic): Salsola tragus 1. Frankenia palmeri 2, Atriplex julacea 1. Loto bryanthii–Isocometum menziesii associatio Heliantho nivei–Astragaletum anemophili associa- nova hoc loco. NTR: Reg. 6005, site 43, 03/25/2005, tio nova hoc loco. NTR: Reg. 13596, site 98, 07/13/ 1 msl, E, 50 m2, 60%, 0.4 m. Physiognomy and 1996, 35 msl, WSW, 10 m2, 50%, 0.2 m. Physiog- habitat: Dune-scrub growing leeward of dune ridges nomy and habitat: Prostrate dune-scrub on alkali with Lycietum brevipedis. Biogeo.: IIc. Biocl.: Tt, Ar, cliffs. Biogeo.: Ib. Biocl.: Tm, Arid, Ho. Floristic Ho. Floristic combination S1 (nanophanerophytic– combination S1 (chamaephytic): Astragalus anemo- chamaephytic): Lotus bryanthii 2, Isocoma menziesii philus 2, Helianthus niveus subsp. niveus 2, Atriplex var. menziesii 2, Croton californicus 1, Atriplex julacea 1. S2 (prostrate subshrub): Carpobrotus magdalenae 1. S2 (prostrate perennial): Camissonia chilensis+. crassifolia 1, Sarcostemma arenarium 1. S2 (winter- Heliantho nivei–Isocometum vernonioidis associa- annual): Amaranthus watsonii 1, Phaseolus acutifo- tio nova hoc loco. NTR: Reg. 11804, site 91, 04/09/ lius var. latifolius 1. 2004, 2 msl, 50 m2, 80%, 0.6 m. Physiognomy and Lycion richii alliancia nova hoc loco loco. habitat: Dune-scrub growing on moist swales, Holotypus: Lycietum brevipedis Peinado et al. leeward of dune ridges with Ephedro californicae– 2005. Lycietum richii. Biogeo.: Ib. Biocl.: Im, Sa, Ho. Nicolletio trifidae–Verbenetalia bajacalifornicae Floristic combination S1 (nanophanerophytic–cha- ordo novus hoc loco. Holotypus: Chaenactido lace- maephytic): Isocoma menziesii var. vernonioides 4, rae–Dyssodion anthemidifoliae alliancia nova. Suaeda taxifolia 1, Helianthus niveus subsp. niveus 1, Oenothero talassaphilae–Jouveion pilosae allian- Lycium californicum 1, Tamarix ramosissima (pl.)+. cia nova hoc loco. Holotypus: Daleo anthonyi– S2 (prostrate perennial): Distichlis spicata 1. Jouveetum pilosae associatio nova. Heliantho nivei–Isocomion menziesii alliancia Palafoxio linearis–Abronion maritimae alliancia nova hoc loco. Holotypus: Camissonio crassifoliae– nova hoc loco. Holotypus: Palafoxio linearis–Dalee- Helianthetum nivei ass. nova. tum tinctoriae ass. nova. Ipomoeo imperati–Jouveetum pilosae associatio Palafoxio linearis–Daleetum tinctoriae associatio nova hoc loco. NTR: Reg. 15005, site 7, 03/28/2005, nova hoc loco. NTR: Reg. 2805, site 62, 03/23/2005, 1 msl, W, 50 m2, 60%, 0.2 m. Physiognomy and 5 msl, E, 200 m2, 40%, 0.2 m. Physiognomy and habitat: Dense community of Jouvea pilosa, on the habitat: Dune scrub on semi-fixed dunes (blowouts). lower part of a continuous foredune, in the rear of the Biogeo.: IIb. Biocl.: Tr, Ar, Ho. Floristic combination upper beach occupied by pioneer vegetation domi- S1 (nanophanerophytic): Dalea tinctoria var. tincto- nated by Sporobolus virginicus. Biogeo.: III. Biocl.: ria 2, Haplopappus sonorensis 1. S2 (chamaephytic Tt, Ar, Ho. Floristic combination: S1 (rhizomatous and herbs on gaps): Atriplex barclayana subsp. grasses): J. pilosa 3. S2 (scattered herbs on gaps): sonorae 1, Palafoxia linearis 1. 123 58 Plant Ecol (2008) 196:27–60

Plantagini ovatae–Chaenactidetum lacerae asso- 05/25/1996, 20 msl, S, 50 m2, 80%, 1.5 m. Physiog- ciatio nova hoc loco. NTR: Reg. 7204, site 76, 04/07/ nomy and habitat: Costal succulent scrub dominated 2004, 35 msl, NNW, 4 m2, 40%, 0.1 m. Physiognomy by thickets of Stenocereus gummosus in rocky places. and habitat: Therophytic pasture on aeolian sands in Biogeo.: Ia. Biocl.: Tm, Sa, Ho. Floristic combination gaps among dune scrubs (Camissonio crassifoliae– S1 (nanophanerophytic scrubs and big succulents): Helianthetum nivei). Biogeo.: IIa. Biocl.: Im, Ha, Ho. Stenocereus gummosus 4, Simmondsia chinensis 3, Floristic combination: Chaenactis lacera 2, Phaseo- Trixis californica 1, Euphorbia misera 1, Bergero- lus acutifolius var. latifolius 2, Camissonia crassifo- cactus emoryi+, Viguiera laciniata+, Lycium an- lia 2, Plantago ovata 1, Coreocarpus parthenoides 1, dersonii+. S2 (chamaephytic scrubs and succulents): Mesembryanthemum crystallinum 1. Eriogonum fasciculatum var. fasciculatum+, Dudleya Sarcostemmato arenarii–Astragaletum magdale- lanceolata+, Mammillaria dioica+. nae associatio nova hoc loco. NTR: Reg. 6505, site 42, 03/25/2005, 0 msl, E, 50 m2, 60%, 0.5 m. Physiognomy and habitat: Dune scrub on the lee of References foredune hillocks created by Abronietum maritimae. Biogeo.: IIc. Biocl.: Tt, Ar, Ho. Floristic combination Anonymous (1995) Sıńtesis Geogra´fica del Estado de Baja S1 (nanophanerophytic): Astragalus magdalenae 2, California Sur. Instituto Nacional de Estadı´stica, Geog- Croton californicus 2, Dalea brandegeei+. S2 (pros- rafıá e Informa´tica. Aguascalientes Anonymous (2001) Sıńtesis Geogra´fica del Estado de Baja trate perennial): Sarcostemma arenarium 1. Abronia California. Instituto Nacional de Estadı´stica, Geografıáe maritima+. S2 (herbs on gaps): Chamaecyse micro- Informa´tica. Aguascalientes mera 1. Axelrod DI (1988) Outline history of California vegetation. In: Sphaeralceo fulvae–Encelietum ventori associatio Barbour MG, Major J (eds), Terrestrial vegetation of California. California Native Plant Society, Davis, pp nova hoc loco. NTR: Reg. 5404, site 76, 04/07/2004, 139–194 2 80 msl, NW, 100 m , 40%, 1.5 m. Physiognomy and Bailey RG (1989) Explanatory supplement to ecoregions map habitat: Shrubland dominated by E. ventorum on of the continents. Environ Conserv 16:307–309 With aeolian dunes, perched at the top of sea cliffs. separate map at 1:30,000,000 Baird SF (1860) Notes on a collection of birds made by Mr. Biogeo.: IIa. Biocl.: Im, Ha, Ho. Floristic combina- John Xantus at Cape San Lucas, Lower California, and tion S1 (nanophanerophytic): Encelia ventorum 2, now in the Museum of the Smithsonian Institution. Proc Sphaeralcea fulva 2, Lycium californicum+. S2 Acad Nat Sci Philadelphia 1859:299–306 (chamephytic): Atriplex julacea 1. S2 (prostrate Barbour MG, De Jong TM, Johnson AF (1975) Additions and corrections to a review of North American Pacific Coast perennial): Camissonia crassifolia 1. S2 (winter- beach vegetation. Madronõ 23:130–134 therophytic): Plantago ovata 1, Dyssodia anthemid- Barbour MG, Johnson AF (1988) Beach and dune. In: Bar- ifolia 1, Perityle emoryi 1, Phaseolus acutifolius var. bour MG, Major J (eds) Terrestrial vegetation of Cali- latifolius 1. fornia. California Native Plant Society, Davis, pp 223– 262 Sporobolo virginici–Ipomoeetum brasiliensis as- Beeftink WG (1965) De zoutvegetaties van ZW-Nederland sociatio nova hoc loco. NTR: Reg. 14605, site 1, 03/ beschouwd in Europees verband. Mededeelingen Land- 28/2005, 0 msl, W, 30 m2, 80%, 0.2 m. Physiognomy bouwhogeschool Wageningen 65(1):1–167 and habitat: Wind-sheltered, prostrate thickets of Biondi E, Cassavechia S (2001) Phytosociological survey of Northern California dunes. Plant Biosyst 135:351–362 Ipomoea pes-caprae subsp. brasiliensis in hollows on Brandegee TS (1891) Flora of the Cape region of Baja Cali- the upper beach. Biogeo.: III. Biocl.: Tt, Ar, Ho. fornia. Proceedings Calif Acad Sci 3:108–182 Floristic combination: S1: I. pes-caprae subsp. bra- Braun-Blanquet J (1979) Fitosociologıá. Bases para el estudio siliensis 4. S2 (herbs on gaps): Sporobolus virginicus de las comunidades vegetales. Blume, Madrid Breckon GJ, Barbour MG (1974) Review of North American 2, Oenothera drummondii var. talassaphila 2, Pacific Coast beach vegetation. Madronõ 22:333–360 Euphorbia leucophylla 1, Palafoxia linearis+. Burk JH (1988) Sonoran desert vegetation. In: Barbour MG, Sporobolo virginici–Jouveetalia pilosae ordo no- Major J (eds) Terrestrial vegetation of California. Cali- vus hoc loco. Holotypus: Oenothero talassaphilae– fornia Native Plant Society, Davis, pp 869–892 CalFlora Database (2004) Berkeley, CA, US. (http:// Jouveion pilosae alliancia nova. www.calflora.org) Trixido californicae–Stenocereetum gummosi as- Cooper WS (1936) The strand and dune flora of the Pacific sociatio nova hoc loco. NTR: Reg. JLA296, site 119, Coast of North America: a geographic study. In: Good- 123 Plant Ecol (2008) 196:27–60 59

speed TH (eds) Essays in geobotany. University of Cali- Kent M, Coker P (1992) Vegetation description and analysis. A fornia Press, Berkeley, pp 141–187 practical approach. Belhaven Press, London Cooper WS (1967) Coastal dunes of California. Memoir Geol Knapp R (1957) U¨ ber die Gliederung der Vegetation von Soc Am 104:1–131 Nordamerika. Geobotanische Mitteilungen 4:1–63 Cope ED (1873) Zoological description. In: Gray OW (ed) Larcher W (2003) Physiological plant ecology, 4th edn. Gray’s Atlas of the United States, with general maps of Springer, Berlin the world, accompanied by descriptions geographical, Lenz LW (1992) An annotated catalogue of the plants of the historical, scientific and statistical. Stedman, Brown & Cape Region, Baja California Sur, Mexico. The Cape Lyon, Philadelphia, pp 32–36 Press, Claremont Delcourt PA, Delcourt HR (1993) Paleoclimates, paleovege- Leoń de la Luz JL, Pe´rez Navarro JJ, Breceda A (2000) A tation, and paleofloras during the late quaternary. In: Flora transitional xerophytic tropical plant community of the of North America Editorial Committee (eds) Flora of Cape Region, Baja California. J Veg Sci 11:555–564 North America: North of Mexico, vol. 1, Oxford Uni- Ludwig JA, Cunningham GL, Whitson PD (1988) Distribution versity Press, New York, pp 71–96 of annual plants in North American deserts. J Arid Delgadillo J (1995) Introduccioń al conocimiento bioclima´tico, Environ 15:221–227 biogeogra´fico y fitosociolo´gico del Suroeste de Nor- Macdonald KB, Barbour MG (1974) Beach and salt marsh teame´rica (Estados Unidos y Me´xico). Tesis Doctoral, vegetation of the North American Pacific Coast. In: Rei- Universidad de Alcala´ de Henares mold RJ, Queen WH (eds) Ecology of halophytes. Aca- Delgadillo J, Peinado M, de la Cruz M, Martıńez-Parras JM, demic Press, New York, pp 175–233 Alcaraz F, de la Torre A (1992) Ana´lisis fitosociolo´gico Mooney HA, Harrison AT (1972) The vegetational gradient on de los saladares y manglares de Baja California, Me´xico. the lower slopes of the Sierra San Pedro Martir in north- Acta Botańica Mexicana 19:1–35 west Baja California. Madronõ 21:439–445 Dice LR (1943) The biotic provinces of North America. Uni- Munz PA, Keck DD (1973) A California Flora and supplement. versity of Michigan, Ann Arbor University of California Press, Berkeley Digby PGN, Kempton RA (1987) Multivariate analysis of Nesom GL (1991) Taxonomy of Isocoma (Compositae: Aste- ecological communities. Chapman and Hall, London reae). Phytologia 70(2):69–114 Durham JW, Allison EC (1960) Geological history of Baja Peinado M, Alcaraz F, Aguirre JL, A´ lvarez J (1994a) Vege- California and its marine faunas. Syst Zool 9:47–91 tation formations and associations of the zonobiomes Evens JM, San S (2005) Vegetation alliances of the San Die- along the North American Pacific coast. Vegetatio guito River Park region, San Diego County, California. 114:123–135 California Native Plant Society, Sacramento Peinado M, Alcaraz F, Delgadillo J, Aguado I (1994b) Fit- Flora of North America Editorial Committee (1993–2005) ogeografıá de la penıńsula de Baja California, Me´xico. Flora of North America: North of Mexico. Oxford Uni- Anales Jardıń Botańico de Madrid 51(2):255–277 versity Press, New York Peinado M, Delgadillo J, de la Cruz M, A´ lvarez J, Aguirre JL Gauch HG (1982) Multivariate analysis in community ecology. (1994c) The coastal salt marshes of California and Baja Cambridge Studies in Ecology, Cambridge University Press California. Phytosociological typology and zonation. Gentry SH (1978) The agaves of Baja California. Occasional Vegetatio 110:55–66 Papers Calif Acad Sci 130:1–123 Peinado M, Alcaraz F, Delgadillo J, Aguirre JL, Aguado I Hastings JR, Turner RM (1965) Seasonal precipitation regimes (1995a) Shrubland formations and associations in Medi- in Baja California, Me´xico. Geografiska Ann A terranean-desert transitional zones of northwestern Baja 47(4):204–223 California. Vegetatio 117:165–179 Heady HF (1988) Valley grassland. In: Barbour MG, Major J Peinado M, Alcaraz F, Aguirre JL, Delgadillo J, A´ lvarez J (eds) Terrestrial vegetation of California. California Na- (1995b) Similarity of zonation within Californian-Baja tive Plant Society, Davis, pp 491–514 Californian and Mediterranean salt marshes. Southwest Heiser CB, Smith DM, Clevenger SB, Martin WC (1966) The Nat 40:388–405 North American Sunflowers (Helianthus). Memoirs Tor- Peinado M, Alcaraz F, Delgadillo J (1995c) Syntaxonomy of rey Botanical Club 22(3):1–218 some halophilous communities of North and Central Hickman JC (1993) The Jepson manual. Higher plants of America. Phytocoenologia 25:23–31 California. University of California Press, Berkeley Peinado M, Alcaraz F, Aguirre JL, Delgadillo J (1995d) Major Howell JT (1957) The California flora and its province. Leaf- plant associations of warm North American Deserts. J lets Western Bot 8:133–138 Veg Sci 6:79–94 Johnson AF (1977) A survey of the strand and dune vegetation Peinado M, Alcaraz F, Martıńez-Parras JM, Delgadillo J along the Pacific and southern coasts of Baja California, (1995e) Una nueva asociacioń de Brometalia rubenti- Mexico. J Biogeogr 7:83–99 tectori en Norteame´rica. Studia Botanica 14:41–46 Keeler-Wolf T (2007) Mojave Desert scrub. In: Barbour MG, Peinado M, Aguirre JL, Delgadillo J (1997) Phytosociological, Keeler-Wolf T, Schoenherr A (eds) Terrestrial vegetation bioclimatic and biogeographical classification of woody of California, University of California Press, Berkeley and climax communities of western North America. J Veg Sci Los Angeles, in press 8:505–528 Kent M, Ballard J (1988) Trends and problems in the appli- Peinado M, Aguirre JL, de la Cruz M (1998) A phytosocio- cation of classification and ordination methods in plant logical survey of the boreal forest (Vaccinio-Piceetea) in ecology. Vegetatio 78:109–124 North America. Plant Ecol 137:151–202 123 60 Plant Ecol (2008) 196:27–60

Peinado M, Delgadillo J, Aguirre JL (2005a) Plant associations Steila D (1993) Soils. In: Flora of North America Editorial of the El Vizcaıńo Biosphere Reserve (Baja California Committee (eds) Flora of North America: North of Sur, Mexico). Southwest Nat 50(2):129–149 Mexico, vol 1, Oxford University Press, New York, pp Peinado M, Aguirre JL, Delgadillo J, Martıńez-Parras JM 47–54 (2005b) A phytosociological survey of the chionophilous Takhtajan A (1986) Floristic regions of the world. University communities of western North America. Part I: temperate of California Press, Berkeley and Mediterranean associations. Plant Ecol 180:187–241 Turner RM, Brown DE (1982) Sonoran Desert scrub. Desert Peinado M, Aguirre JL, Delgadillo J, Gonza´lez J, Martıńez- Plants 4:181–222 Parras JM (2005c) A phytosociological survey of the USDA, NRCS (2005) The PLANTS Database, Version 3.5 chionophilous communities of western North America. (http://www.plants.usda.gov). Data compiled from various Part II: boreal associations. Plant Ecol 180:243–256 sources by Mark W. Skinner. National Plant Data Center, Peinado M, Macıás MA´ , Delgadillo J, Aguirre JL (2006) Major Baton Rouge, LA 70874-4490, USA plant communities of North America’s most arid region: Van Dyke EC (1919) The distribution of insects in western the San Felipe Desert, Baja California, Me´xico. Plant North America. Ann Entomol Soc Am 12:1–12 Biosyst 140(3):1–17 Vaseck FC, Barbour MG (1988) Mojave Desert scrub vege- Peinado M, Aguirre JL, Delgadillo J, Macıás MA´ (2007) tation. In: Barbour MG, Major J (eds) Terrestrial vege- Zonobiomes, zonoecotones and azonal vegetation along tation of California. California Native Plant Society, the Pacific coast of North America. Plant Ecol Davis, pp 835–868 191(2):221–252 VAST (2005) Missouri Botanical Garden´s Vascular Tropicos Raven PH (1963) Amphitropical relationships in the flora of database. (http://www.mobot.mobot.org/W3T/search/ North and South America. Q Rev Biol 38:151–177 vast.html). Saint Louis Rebman J (1995) Biosystematic study of Opuntia subgenus Weber HE, Moravec J, Theurillat JP (2000) International code Cylindropuntia, the chollas of Lower California. Ph. D. of phytosociological nomenclature, 3rd edn. J Veg Sci Thesis, Arizona State University 11(5):739–768 Rivas-Martıńez S (1997) Syntaxonomical synopsis of the West NE (1988) Intermountain deserts, shrub steppes, and North America natural potential vegetation communities, woodlands. In: Barbour MG, Billings WD (eds) North 1. Itinera Geobot 10:5–147 American terrestrial vegetation. Cambridge University Rivas-Martıńez S (2005) Global bioclimatics. Madrid (http:// Press, Cambridge, pp 209–230 www.ucm.es/info/cif) Westhoff V, van der Maarel E (1973) The Braun-Blanquet Rivas-Martıńez S, Wildpret W, del Arco M, Rodrı´guez O, Pe´rez approach. In: Whittaker RH (ed) Ordination and classifi- de Paz PL, Garcıá-Gallo A, Acebes JR, Dıáz TE, Fernań- cation of communities. Dr. W. Junk, The Hague, pp 617– dez-Gonza´lez F (1993) Las comunidades vegetales de la 626 Isla de Tenerife (Islas Canarias). Itinera Geobot 7:169–374 Westman WE (1983) Xeric Mediterranean-types shrubland Rzedowski J (1978) VegetaciońdeMe´xico. Limusa, Me´xico, associations of Alta and Baja California and the com- DF munity/continuum debate. Vegetatio 52:3–19 Sawyer JO, Keeler-Wolf T (1995) A manual of California Wiggins IL (1969) Observations on the Vizcaıńo Desert and its vegetation. California Native Plant Society, Sacramento biota. Proc Calif Acad Sci 36:317–346 Shreve F (1936) The transition from desert to chaparral in Baja Wiggins IL (1980) Flora of Baja California. Stanford Univer- California. Madronõ 3:257–264 sity Press, Stanford Shreve F, Wiggins IL (1964) Vegetation and flora of the Sonoran Zippin DB, Vanderwier JM (1994) Scrub communities Desert, 2 vols. Stanford University Press, Stanford descriptions of the Baja California, Mexico. Madronõ Sneath PHA, Sokal RR (1973) Numerical taxonomy. Freeman, 41(2):85–119 San Francisco

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