Systematics and Relationships of Fallugia (Rosoideae—Rosaceae) James Henrickson California State University, Los Angeles
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Aliso: A Journal of Systematic and Evolutionary Botany Volume 20 | Issue 1 Article 3 2001 Systematics and Relationships of Fallugia (Rosoideae—Rosaceae) James Henrickson California State University, Los Angeles Follow this and additional works at: http://scholarship.claremont.edu/aliso Part of the Botany Commons Recommended Citation Henrickson, James (2001) "Systematics and Relationships of Fallugia (Rosoideae—Rosaceae)," Aliso: A Journal of Systematic and Evolutionary Botany: Vol. 20: Iss. 1, Article 3. Available at: http://scholarship.claremont.edu/aliso/vol20/iss1/3 Aliso. 20( I), pp, 1-15 © 200 I. by The Rancho Sant a Ana Botanic Ga rden. C lare mo nt. CA 9 17 11-3157 SYSTEMATICS AND RELATIONSHIPS OF FALLUGIA (ROSOIDEAE-ROSACEAE) JAMES H ENR ICKSON Department of Biological Scien ce Cal ifornia State University Los Angele s, Calif. 90032 ABSTRA CT The pap er presents a systematic monograph of Fal lugia (Rosoide ae, Rosaceae) co nsisting of one var iable species, Fallugia paradoxa. Morph olog ical. cy tolog ical and mole cul ar data clea rly support its relationship with Geum s.l. rather than Pu rshia- Cowania. with whic h it is often allied. The spec ies was nam ed tw ice independently in 1825 from the specimens and drawings, respectively. assembled by Sesse and Mocifio for their prop osed Flora Mexicana. The paper discusses the nomenclatural history, morph ological variation, and the polygarno-d ioec ious mode of reproduction of the species. No infraspecific taxa are recogni zed. Key word s: Apache plume, Fallugia, Rosaceae, Rosoideae. systema tics. INTRODUCTION tral New Me xico , and throughout the Chihuahu an De se rt, parti cul arly in ce ntral Coahuila. SEM was done Fallugia paradoxa (D. Don) Endl., the Apache with a Jeol JSM T200 Scanning Electron Microscope plume, is a common shrub in de serts of the south at CSLA from dried materials . western United States and northern Mexico . The spe cies has long been conside red related to Cowania RESU LTS stans buriana Torr., the cliffros e now placed in Purshia as Purshia stansburiana (Torr.) Henrickson (Henrick Comparative Structure of Fallugia, Purshia son 1986). In most phylogenetic treatments dealing (Cow ania) and Geum with the relation ship of rosaceous ge nera (e.g., Ben tham and Hooker 1862; Focke 1894 ; Rydberg 1913; Fallugia is often sympatric with Purshia stansbu Schulz-Menz 1964) Fallugia is placed with Cowania riana, and the two share the following characteri stics. near or between Dryas and Geum (se nsu lato) within Both are shrubs in the southwes tern deserts, with fi the tribe Dryoid eae of the subfamily Rosoideae . Like brous bark that se parates into many thin , cinnamon wise, in most so uthwes tern floras usin g a phylogenetic brown layers. Both have a basic ves riture of unicellular arrangement of genera, Fallugia lies between Cowania hairs along with pinnately divided leaves that are green and Geum (Abrams 1944; Kearney and Peebl es 1951; above, and stro ngly ves titured beneath with revolute Mun z 1959). However, rece ntly publ ished cy to log ical margins that co nverge tow ards thickened ce ntral vein s. data (Mc Arthur et al. 1983) and molecular data (Mor In both taxa, the leaves are crowded on long and short gan et al. 1994) give strong evidence for Fallugia be shoots, and as in many Rosaceae, the blades abscise ing closely related to Geum, but not Cowania and Cer above the persistent conjoined leaf bases and stipules. cocarp us. Both produce large flow ers. The hypanthia bear 5 Whil e cytolog ica l and molecular data have provided large, imbricate sep als, 5 orbicular petals, many sta strong evidence of the relationship of Fallugia, it will men s with yellow, longiscidal anthers borne on slender be shown that the same conclusion can be obtained filaments, and multiple ovaries with terminal, non-ar from even a cursor y examination of morphological ticulating sty les that form accrescent, plumose awn s and anatomica l character istics. on the mature I-seeded achenes. Th e seeds have basal radicles and no endosperm. In both, the fruit s are wind MAT ERIA L S AND METHOD S dispersed . Fallugia (Fig. 1-1 9), how ever, has a large number Thi s study is based primarily on empirical evidence of distinctive traits. In sa ndy arroyo s, Fallugia pro derived from herbarium and field ob servations of Fal duces rhizomes and tend s to form colonies (Fig. 4, 5). lugia, Purshia (Cowania), Geum, and from the litera Vegetative portions have a distinctive orange-rust-col ture. Material of Fallugia was borrowed from or ob ored lepidote understory vestiture (Fig. 24) and seed served at ARIZ, ASU , A-GH, CSLA, JEPS, MO , NY, ling leaves have scattered uniseriare, multi cellular, RSA-POM, TEX-LL, UC, UNM, and US and ob stipitate glands (Fig. 26; Kyle et al. J 986). Its mature served in the fi eld in eastern California, Arizona, ce n- leaves are egl andular, thin and pinn ati fid, or sometimes 2 Henri ckson ALISO Fig. 1-5. Fallugia paradoxa growth habil.-I. Pistillate fruiting plant ca. 1.2 m tall from E San Bernardino Co .. California (Clark Mountains).-2. Close-up of fru iting pistillate flowers showing distinctive "Apache" plumes.-3. Young stem ca. 1.2 ern in diameter showing fibrous bark.-4. Underground stems showing development of lateral sucker shool.-5. flowering plant showing isolated separate plants that have developed from sucker shoo ts of parent plant. Magnifications indicated in text . bipinnatifid (Fig. 27 , 28 ). The flowers are produced at that in some plants the terminal flowers of a stem may the tips of elongated stems, either solitary or in irreg be perfect and produce fruit. ular corymbs (Fig. 6, 17). The rim of the hemispher In contrast, Pursh ia (Cowania) has been shown to ical hypanthium has conspicuous leaf-like bracts that have a deep root sys tem. grows in rocky habitats, and alternate with the sepa ls to form an epicalyx (Fig. 29, is not rhizomatous (Henrickson in prep.). It has mul 30). The hypanthia are densely hirsute within. The se tiseriate sti pirate glands on stems and hypanthia and pals have one or more linear, leaf-like terminal or sub se ssile glands imbedded in the leaf surfaces. The flow terminal appendages (Fig. 29, 30). The petals are ers are borne on the lateral short-shoots all along the white; the ovaries number 50-120, borne in a spiral upper stems. The rim of the obconic hypanthia lack s pattern on a raised conica l receptacle each on a dis an epicalyx ; the petals are cream-yellow in color, the tinct, hirsute stalk, and each ovary has 2 superposed ovaries are far fewer (4-10) and whorled at the base amphitropous basal ovules, one borne above the other of the hypanthium, and the stigmatic surfaces extend (Fig. 15). The fruit wall s are 2-veined, with thin lateral 2-3 mm down one side of the styles. The ovules are walls, and the stigmatic surface extends about 0.2-0.3 solitary, but, as in Fallugia. amphitropous with a basal mm down the style (Fig. 16). Furthermore, FalLugia is micropyle. The mature fruit walls are thick and strong polygarno-dioecious, with some plants producing pis ly 10-12-veined and all flowers are perfect and com tillate flowers (with reduced, sterile stamens; Fig. 32, plete. Furthermore, species of Purshia (Cowania), like 34 ) and other plants have larger staminate flowers with Cercocarpus, form a symbiotic relationship with the fertile stamens with larger anthers on longer filaments Actinomycete Frankia, which results in nodulation (Fig. 31, 33 ), and pistil s that do not develop, except and nitrogen fixation in the host roots (Nelson 1983, VOLUME 20, NUMBER I Fallugio, Rosaceae 3 see Schwintzer and Tjepkema 1990). Such nodulation Madro-Tertiary Geoflora (Axelrod 1958). Neverthe and association has not been reported in Fallugia. less, a number of characteristics appear to be confined Many of the shared characters appear associated to Fallugia: the distinctive orange-rust lepidote-stellate with adaptation to desert habitats, i.e., the woody vestiture, two ovules per ovary, and its polygamo-di growth habit, the dissected leaves with revolute mar oecious mode of reproduction. gins, the long- and short-shoot development. Probably Studies of Rosaceae pollen also favor relationships the most conspicuous difference lies in the epicalyx of of Fallugia with Geum and Waldsteinia. Hebda and leaf-like bracts alternating with the sepals on the rim Chinnappa (1994) note that there is distinct scuJpturing of the hypanthium in Fallugia (Fig. 29, 30) . This fea variation in the Rosoideae and that the above noted ture occurs elsewhere in the subfamily Rosoideae, in three genera (along with Coluria and Orthurus-seg tribe Potentilleae (i.e., Potentilia. Fragaria, Ivesia, regates of Geum s.l.) share a distinct striate microper Horkelia, Sibbaldia, etc.), but in that tribe, the styles forate sculpturing pattern. are lateral on the ovary and are deciduous at maturity. The decision as whether to relate Fallugia (n = 14) An epicaJyx also occurs in largely herbaceous Geum with Geum (x = 7) or Purshia (Cowania) (n = 9), is and allies (Geum, Waldsteinia. Colura etc.), in which strongly influenced by cytological data. Cowania, Pur the styles are, as in Fallugia, terminal (not lateral) shia, Cercocarpus and Dryas are all n = 9, as are most (Fig. 16). Spiraeoideae and their achene-bearing derivatives, e.g ., Geurn s.l. is highly diverse, consisting of up to 12 the follicle-bearing Sorbaria and Chamaebatiaria giv subgenera (Gajewski 1957, 1959); several of these are ing rise to the achene-bearing Chamaebatia and Ad treated as separate genera by Rydberg 1913, Yuzep enostoma.