Pacific Science (1990), vol. 44, no. 3: 258-264 © 1990 by University of Press. All rights reserved

Chromosome Counts from the Flora of the Juan Fernandez Islands, . 111. 1

BYUNG YUN SUN,2 Too F. STUESSY,3 and DANIEL J. CRAWFORD3

ABSTRACT: Thirty-four chromosome counts are reported from populations in 20 species from Masafuera in the Juan Fernandez Islands, Chile. New species counts are in Abrotanella crassipes (2n = 18), Carpobrotus aequilaterus (n = 9), Coprosma pyrifolia (n = 22), Drimys confertifolia (n = ca. 43), Euphrasia Jor­ mosissima (n = 44), debilis (n = 8), and UrticaJernandeziana (n = ca. 11). A new chromosomal level for Hypochoeris glabra (n = 12) also is provided. The taxonomic implications ofcertain ofthese counts are discussed. These data help extend chromosomal information for endemic taxa of the archipelago as part ofbroad evolutionary studies on the origin ofthe vascular . This study again emphasizes the absence ofaneuploid or euploid chromosomal alterations during speciation within the archipelago.

ONE OF THE MOST FASCINATING oceanic archi­ (Spooner et al. 1987). The present paper adds pelagoes of the Pacific is the Juan Fernandez new data regarding the flora of the archipela­ Islands. These small islands lie 600 km west go from material collected from the younger ofcontinental Chile at 33° S latitude. Having island, Masafuera, on oUr expedition in 1986. never been connected to the mainland, the Juan Fernandez archipelago has been the site of evolutionary diversification of a unique MATERIALS AND METHODS flora. Sixty-nine percent ofthe species ahd 18 percent of the genera of flowering plants are Flower buds were collected in the field, endemic (Skottsberg 1956), and there also preserved in modified Carnoy's fixative (4 exists one endemic family (Lactoridaceae). chloroform: 3 absolute ethanol: I glacial ace­ To understand patterns and processes of tic acid), transferred to 70% ethanol back in evolution in the endemic flora of the Juan the laboratory, and stored under refrigera­ Fernandez Islands, collaborative studies have tion. Slide preparations were made by squash­ been carried out in the botanical laboratories ing young florets and examining developing of Ohio State University and the University anthers for meiotic divisions in the pollen ofConcepcion, Chile. One ofthe emphases of mother cells. Acetocarmine stain was used these studies has been the investigation of and preparations were made semipermanent chromosome numbers to reveal the impor­ with Hoyer's medium. One count (for Abrota­ tance ofchromosomal change (i.e., aneuploi­ nella crassipes) was obtained by a squash of dy and euploidy) in the evolution of the cells undergoing mitotic divisions in the devel­ endemic flora. Two surveys have already been oping embryo after fertilization. published from material collected on expedi­ tions in 1980 (Sanders et al. 1983) and in 1984 RESULTS

1 This work was supported in part by NSF grant Thirty-four new chromosome counts for BSR8306436. Manuscript accepted October 1989. taxa growing on Masafuera are listed in Table 2 Department of Biology, Chonbuk National Uni­ versity, Chonju, 560-756, Korea, 1. First counts are reported for seven species: 3 Department of Botany, Ohio State University, 1735 Abrotanella crassipes (Asteraceae), Carpobro­ Neil Avenue, Columbus, Ohio 43210. tus aequilaterus (Aizoaceae), Coprosma pyri- 258 Chromosome Counts from Chilean Flora-SUN, SnrnsSY, AND CRAWFORD 259

TABLE I

CHROMOSOME NUMBERS OF TAXA FROM MASAFUERA, JUAN FERNANDEZ ISLANDS, CHILE

MEIOTIC CHROMOSOME TAXON NUMBER" VOUCHERb

Aizoaceae *Carpobrotus aequilaterus (Haw.) N.E. Br. 9 Quebrada Mono, SL 8329 Asteraceae *Abrotanella crassipes Skottsb. 2n = 18' Los Inocentes, A 9350 Erigeron rupicola Phil. 27 Tierras Blancas, SR 8450 **Hypochoeris glabra L. 12 Cordon Atravesado, SV 9097 H. radicata L. 4 Quebrada Pasto, SL 8391; Quebrada Ovalo, SG 9002; Cordon Atravesado, SV 9098 Lagenophora hariotii Franch. 7II + 41 Cordon Inocentes, SP 9553 Brassicaceae Nasturtium ojficinale R. Br. 16 Quebrada Varadero, RA 8280 Campanulaceae Wahlenbergia masafuerae (phil.) Skottsb. 11 Quebrada Casas, RL 8006; Quebrada Vacas, RL 8045; Quebrada Sandalo, V 8145; Quebrada Pasto, SL 8403; between Quebradas Vacas and Guaton, SRL 9317; Quebrada Mono, G. Lopez s.n. Caryophyllaceae Spergularia confertiflora Steud. 36 Chorro de Florida, V 8127; Quebrada Casas, SL 8317; Quebrada Tongo, SR 8465 Ericaceae Pernettya rigida (Bert.) DC. 33 Quebrada Pasto, AR 9201 Myrtaceae Myrceugenia schultzei Johow 11 Plano de Sanchez, RAV8281 Myrteola nummularia (Poit.) Berg 22 Cordon Inocentes, SP 9550 Piperaceae Peperomia berteroana Miq. 2211 + 21 Quebrada Casas, RL 8004 *Coprosma pyrifolia (Hook. et Am.) Skottsb. 22 Quebrada Pasto, A 9387 granadensis (L. f.) Druce. 22 Cordon Inocentes, SGP 9529 Scrophulariaceae *Euphrasia formosissima Skottsb. 44 Quebrada Guaton, AG 9105; between Quebradas Vacas and Guaton, SRL 9318; Cordon Inocentes, AR 9591 *Parietaria debi/is Forst. 8 Quebrada Sanchez, SL 8380; Quebrada Casas, SVAG 9063 *Urticafernandeziana (Rich.) Ross. ca. II Cordon Atravesado, SV 9090 venustus (Phil.) Robins. 18 Quebrada Larga, RA V 8290 Winteraceae *Drimys confertifolia Phil. ca. 43 Quebrada Ovalo, SVAG 9070; Quebrada Pasto, SL 9260; Cordon Inocentes, SP 9551

*First report for the taxon. ** New chromosome level for the taxon. "Numbers represent bivalents except where noted otherwise. •A = A. Landero, G = L. Gaete, L = T. Lammers, R = E. Ruiz, P = J. Sepulveda, S = T. Stuessy, and V = H. Valdebenito. 'From cells of the young embryo. 260 PACIFIC SCIENCE, Volume 44, July 1990 folia (Rubiaceae), Drimys confertifolia (Win­ ferred Crocidium to the Senecioneae. Norden­ teraceae), Euphrasia formosissima (Scrophu­ starn (1977), however, believed that these lariaceae), Parietaria debilis (Urticaceae), and genera are out of place geographically and fernandeziana (Urticaceae). Twenty­ morphologically in the Senecioneae. The ba­ two additional counts are for taxa reported sic chromosome number of the Anthemideae previously, one ofwhich is a new number. is x = 9 with many numbers n = 9 and n = 18 (Heywood and Humphries 1977). Known chromosome numbers in Ischnea are 2n = 18 (Borgmann 1964), and n = 9 in Crocidium DISCUSSION (Ornduffet al. 1963, Spellenberg 1964, Schaack Discussions are provided on some of the et al. 1974). Our first count of 2n = 18 for counts reported here, alphabetically by fam­ Abrotanella crassipes and the previous report ily, with focus on first reports for species. of 2n = 18 for A. emarginata Cass., endemic General statements on numbers of species to the Falkland Islands (Moore 1967), coin­ counted within genera and their chromosomal cides with counts for related taxa whether one data come from the standard chromosomal in­ emphasizes placement in the Anthemideae or dices (Darlington and Wylie 1955, Cave 1958­ Senecioneae. Abrotanella crassipes is appar­ 1965, Ornduff 1967-1969, Fedorov 1969; ently related most closely to A. mosleyiSkotts. Moore 1970-1977; Goldblatt 1981-1988). (Skottsberg 1922), but the latter species from Patagonia is still unknown chromosomally. AIZOACEAE: Carpobrotus N.B. Br., once Hypochoeris L., with about 70-100 species included in Mesembryanthemum s.l., which is mainly distributed in South America and now divided into a hundred or more genera Europe, is divided into two subgenera based or sometimes even treated as a separate on characteristics of the pappus (Burkart family, Mesembryanthemaceae (Herre 1971), 1974, Gustav 1987). Subgenus Hypochoeris 24 is a genus with species mainly distributed comprises only two species (H. glabra and H. in South Africa, , , and radicata), which are native to Europe and Pacific regions (Shaw 1973). Only four species have been introduced to South America, in­ are known chromosomally and all are 2n = 18 cluding the Juan Fernandez Islands (Skotts­ (Vos 1947, Snoad 1951). Our new count of berg 1922, Burkart 1974, Gustav 1987). Chro­ n aequilaterus, = 9 for C. native to coastal mosomally, H. glabra has been consistently sands of Chile from 30° to 40° S (Blake 1969) counted from 13 populations as n = 5 except and apparently introduced to the islands, is for three reports documenting two other levels consistent with othercounts within the genus. (n = 4, Turner 1970; n = 6, Negodi 1935, ASTERACEAE: Abrotanella Casso is a genus of Heiser and Whitaker 1948). The island popu­ 14 species distributed in Australia, Tasmania, lations of H. glabra (e.g., Solbrig 3693, SV New Guinea, New Zealand, and the Falkland 9097, AR 9256, A 9380) look very different Islands. Abrotanella crassipes is endemic to from typical H. glabra in overall habit. They the Juan Fernandez Islands and is confined to are much shorter (4-7 cm) than typical repre­ the highest ridge (Los Inocentes) ofthe young­ sentatives (30-40 cm) and have fewer flowers er island, Masafuera. The relationships of the per head. We have seen one specimen similar genus are still problematical. It has usually to the island form collected from the Province been placed in the Anthemideae (Heywood of Pichincha, Ecuador at 3600 m (Little & and Humphries 1977), but Robinson and Paredes 6945, US). We regard these variations Brettell (1973) suggested that it belongs in the as ecological races of H. glabra rather than Senecioneae based on microfeatures of the distinct species. However, our count ofn = 12 anthers and corollas. They favor a position from a population located in Cordon Atrave­ with Ischnea (also placed by most workers in sado at 1200 m on Masafuera (SV 9097) is the Anthemideae) in the Senecioneae near very unusual compared with previous reports, Crocidium. Based upon pollen ultrastructur­ which have not yet revealed polyploidy. Park­ al features, Skvarla and Turner (1966) re- er (1975) reported frequent natural and artifi- Chromosome Counts from Chilean Flora-SUN, STUESSY, AND CRAWFORD 261

cial hybridizations between H. glabra and H. known from the eastern side of the Pacific radicata and suggested possible gene flow (Fosberg 1968), have been described as en­ between them. The voucher specimen of our demic to the Juan Fernandez Islands (Skotts­ count is clearly H. glabra and shows no berg 1922): C. pyrifolia (H. & A.) Skottsb. and tendency toward H. radicata. The meiotic C. oliveri Fosberg [the earlier name of the chromosomes show clear bivalents, which latter, C. hookeri (G. Don) Oliver, was de­ also help exclude the possibility of hybrid termined to be a later homonym of C. hookeri origin for our material. Stapf of Borneo by Fosberg (1968), who renamed it C. oliveri]. Our first chromosome CAMPANULACEAE: Wahlenbergia masafuer­ count of n = 22 for C. pyrifolia is consistent ae has been counted previously as n = ca. 11 with most ofthe previous counts ofthis genus (Spooner et al. 1987). Our exact counts here (36 of the 56 species have been counted as from six populations all with n = 11 confirm n = 22). This probably represents the tetra­ the previous report. The previous count came ploid level on an ancestral base of x = 11 from a population located in Quebrada Casas (Sanders et al. 1983). Skottsberg (1922) re­ (Pacheco & Ruiz 6408), and we have counted marked that C. pyrifolia is most closely related other individuals from this same locality (RL to C. laevigata of Rarotonga, New Zealand, 8006). We have also now sampled three popu­ and C. oliveri ( = C. hookeri) is closest to C. lations toward the northern part ofthe island foliosa of Hawaii, and that the affinity be­ (SL 8403, V 8145, and G. Lopez s.n.), as well tween the two Juan Fernandez island species as from the highest ridge (1050 m, S et at. is remote. Fosberg (1986), however, suggested 9317). This latter material is small in habit, that the two island species are not only the and the vegetative parts are more hispid than closest to each other, but also close to Poly­ other known collections. An even more strik­ nesian species such as C. cookei Fosberg. ing morphological variant is confined to the Among the above-mentioned species, only C. dry coastal cliffs between Quebrada Casas and laevigata is known chromosomally, and it is Quebrada Vacas at 3 m elevation. Here the n = 22 (Beuzenberg 1983). Considering the plants have shorter internodes (2-3 mm), uniformity ofchromosome numbers through­ resulting in a more compact habit, and they out the genus, it would not be surprising if all are only weakly hispid. All of the sampled these close relatives were also n = 22. populations are now known as n = 11, which suggests that W. masafuerae contains con­ SCROPHULARIACEAE: Ofthe 19 South Amer­ siderable morphological variation and/or ican species of Euphrasia (Barker 1982), only plasticity that is unrelated to change in chro­ one has been counted chromosomally, as mosome number. n = 44 from a population from the Falkland Spergularia confertiflora has been counted Islands (E. antarctica Benth.: Moore 1967). previously as n = 36 from two populations on Our first count for E. formosissima of n = 44 Masatierra (Sanders et al. 1983). Our three from three populations places this species also new counts also of n = 36 are the first from at the octoploid level within the genus, which populations on Masafuera and are consistent appears to be based on x = 11 (Barker et al. with previous reports for this species. The 1988). The relationship ofE.formosissima, the relationships of the species of the Juan Fer­ only species of sect. Paradoxae, to the other nandez Islands to those ofmainland Chile are groups is inconclusive. Although there has not yet clear. Spergularia confertiflora may be been some agreement of a remote tie to the related to S. remotiflora Steud. (Skottsberg South American species of sect. Trifidae, E. 1922), and S. masafuerana may be related to formosissima also has been suggested to be the cosmopolitan species S. media (L.) Presl. related to taxa of New Zealand (Du Rietz (Skottsberg 1953). Cytological study of S. 1932, 1948) or even the northern hemisphere masafuerana and mainland species would be (Skottsberg 1922). In the most recent mono­ helpful in this regard. graph, Barker (1982) speculated that sect. Two species of Coprosma, the only ones Paradoxae of the Juan Fernandez Islands is 262 PACIFIC SCIENCE, Volume 44, July 1990 closely related to sect. Novaezeelandiae, a Chile, is also known as n = ca. 18 (Spooner group of four small New Zealand annuals et al. 1987). Sanders et al. (1983) suggested with unique acropetal patterns of branch the basic number of the genus to be x = 19, development and pubescence of the anther based on n = 38 from the closest genus, Ci­ slits. Among taxa of the southern Pacific tharexylum (c. spinosum L., Mehra 1976), but region, Barker (1982) recognized four sections it seems more likely now that the base is that appear to be very closely related: sect. x = 18. Sanders et al. (1983) suggested that Paradoxae of Juan Fernandez, sect. Trifidae the ancestral base for this entire group was of South America, sect. Novaezeelandiae of probably x = 9, and our exact count ofn = 18 New Zealand, and sect. Anagospermae also of for R. venustus helps support this contention. New Zealand. Among these, the two sections The two species of Rhaphithamnus, therefore, for which chromosomal information is now would be at the tetraploid level. More chro­ available, sect. Trifidae (E. antarctica, n = 44) mosome counts of in mainland and sect. Paradoxae (E. formosissima, n = Chile would be helpful. 44), are both at the octoploid level. All other counts known in the genus are n = 11 or WINTERACEAE: Drimys has four species n = 22, except for a recent report of seven confined to Central and South America (Smith Australian species showing hexa, deca, and 1943). Two of them are already known chro­ dodecaploidy (Barker et al. 1988). The octo­ mosomally, as n = 43 for D. winteri J. R. & ploid level, therefore, stands out as a distinc­ Forst. (Raven and Kyhos 1965) and n = 43 tive chromosomal line within the genus. In for D. granadensis var. mexicana (DC.) Sm. this context, it is possible that the other Pacific (Ehrendorfer et al. 1968). Our first count of sections, sect. Novaezeelandiae and sect. Ana­ n = ca. 43 for D. confertifolia from three gospermae, might also occur at this level. populations on Masafuera is consistent with previous reports for this genus. It also sug­ URTICACEAE: Parietaria, with about 30 spe­ gests that there has been no change in chro­ cies mainly distributed in temperate regions mosome number during speciation of D. con­ (Skottsberg 1956) contains diverse chromo­ fertifolia from its closest relative on the con­ some numbers ofn = 7,8,10, and 13. Our first tinent, D. winteri. Raven and Kyhos (1965) count ofn = 8 for P. debilis is consistent with speculated that the ancestral base of Drimys the above reports. Larsen (1963) speculated might be x = 7, and therefore D. confertifolia the base numbers ofthe genus to be x = 7 and would be a dodecaploid. Raven and Kyhos 13 (perhaps also x = 10 for P. arborea). How­ (1965) suggested the base number of Winter­ ever, it is more likely that the base num­ aceae to be x = 43, but with the related genus = = ber is x 7 or 8, with n 13 already at the Tasmannia R. Br. as x = 13, it would seem tetraploid level. that Drimys is probably an aneuploid at least Our first count of n = ca. 11 for Urtica at the hexaploid level. fernandeziana, endemic to Masafuera, is con­ Once again the chromosomal data suggest sistent with previous reports of x = 11, 12, or that few aneuploid or euploid changes have 13 for the genus. Skottsberg (1956) stressed occurred during speciation in the vascular that this species is very distinctive, morpho­ plants ofthe Juan Fernandez Islands. Exami­ logically and regarded it as an ancient type. nation of 35% of the endemic species shows This seems improbable because of the young no aneuploid nor alloploid evolutionary re­ geological age of Masafuera (1-2 m.y.). lationships. This situation appears similar to VERBENACEAE: Rhaphithamnus venustus has the results from Hawaii obtained by Carr been counted previously as n = ca. 18 from (1978, 1985) and for the Bonin Islands by a population on Masatierra (Sanders et al. Ono (in press). The reason for this tendency 1983). Our first count from a population on toward chromosomal conservatism in ocean­ Masafuera as n = 18 confirms the previous ic settings may be related to the disruptive report. The only other species in the genus, R. nature of such chromosomal alterations in spinosus (Juss.) Moldenke from continental upsetting adaptive character complexes that Chromosome Counts from Chilean Flora-SUN, STUESSY, AND CRAWFORD 263 are essential for survival in the microhabitats CARR, G. D. 1978. Chromosome numbers of in the islands. For adaptive radiation to pro­ Hawaiian flowering plants and the signifi­ ceed along lines of strong directional selec­ cance of cytology in selected taxa. Am. J. tion, such drastic alterations may lead to Bot. 65: 236-242. ill-adapted progeny. ---. 1985. Additional chromosome num­ bers ofHawaiian flowering plants. Pac. Sci. 39: 302-306. CAVE, M. S., ed. 1958-1965. Index to ACKNOWLEDGMENTS chromosome numbers, 1956-1964 & Suppl. With sincere appreciation we thank the University ofNorth Carolina Press, Chapel Korean Science and Engineering Foundation Hill. for a postdoctoral fellowship for the senior DARLINGTON, C. D., and A. P. WYLIE. 1955. author during 1989 for research at Ohio State Chromosome atlas of flowering plants, 2d University; CONAF of Chile for permission ed. George Allen and Unwin, Ltd., Lon­ to collect in the Juan Fernandez archipelago, don. and in particular Ivan Laeva, Chief of the Du RIETZ, G. E. 1932. Two new species of Robinson Crusoe National Park, who facili­ Euphrasia from the and their tated our research in many ways; our field phytogeographical significance. Sven. Bot. assistants L. Gaete, T. Lammers, A. Landero, Tidskr. 25: 500-542. E. Ruiz, and H. Valdebenito; and the local ---. 1948. Taxonomical notes on some fishermen and CONAF guides, especially B. Tasmanian species of Euphrasia. I. Eu­ and G. Lopez, who helped greatly in our work phrasia striata R. Br. and E. gibbsiae Du on Masafuera. Rietz n.sp. Sven. Bot. Tdskr. 42: 99-115. EHRENDORFER, F., F. KREND, E. HABELER, and W. SAUER. 1968. Chromosome num­ bers and evolution in primitive angiosperms. LITERATURE CITED Taxon 17: 337-353. BARKER, W. R. 1982. Taxonomic studies in FEDOROV, A. A., ed. 1969. Khromosomnye Euphrasia L. (Scrophulariaceae). A revised chisla tsvetkovykh rasteny [Chromosome infrageneric classification, and a revision of numbers of flowering plants]. Academy of the genus in Australia. J. Adelaide Bot. Science U.S.S.R., Leningrad. Gard.5:1-304. FOSBERG, F. R. 1968. Studies in Pacific Ru­ BARKER, W. R., M. KIEHN, and E. VITEK. biaceae. VIII. The Juan Fernandez Co­ 1988. Chromosome numbers in Australian prosmas. Brittonia 20: 291-294. Euphrasia (Scrophulariaceae). Plant. Syst. GOLDBLATT', P., ed. 1981-1988. Index to plant Evol. 158: 161-164. chromosome numbers 1975-1985. Missouri BEUZENBERG, E. J. 1983. Contributions to a Botanical Garden, St. Louis. chromosome atlas of the New Zealand GUSTAV, H. 1987. Illustrierte flora von Mit­ flora-24. Coprosma (Rubiaceae). N. Z. J. teleuropa. Spermatophya, Band VI. An­ Bot. 21 :9-12. giospermae Dicotyledones 4: 1008-1016. BLAKE, S. T. 1969. A revision of Carpobrotus HEISER, C. B., and T. W. WHITAKER. 1984. and Sarcozona in Australia, genera allied to Chromosome number, polyploidy and Mesembryanthemum (Aizoaceae). Contr. growth habit in California weeds. Am. Queensl. Herb. 7: 1-65. J. Bot. 35: 179-186. BORGMANN, E. 1964. Anteil der polypoiden in HERRE, H. 1971. The genera of the Mesem­ der flora des Bismarcksgebirges von Ost­ bryanthemaceae. Nasionale Boekhandel neuguinea. Z. Bot. 52: 118-172. Ltd., Cape Town and Johannesburg. BURKART, A. 1974. Flora ilustrada de Entre HEYWOOD, V. H., and C. J. HUMPHRIES. 1977. Rios (), Part VI. Instituto Nacio­ Anthemideae-Systematic review. Pages nal de Tecnologia Agropecuaria, Buenos 851-898 in V. H. Heywood, J. B. Har­ Aires. borne, and B. L. Turner, eds. The biology 264 PACIFIC SCIENCE, Volume 44, July 1990

and chemistry of the Compositae. Aca­ RIGUEZ. 1983. Chromosome numbers from demic Press, London. the flora of the Juan Fernandez Islands. LARSEN, K. 1963. Contribution to the cytol­ Am. J. Bot. 70:799-810. ogy of the endemic Canarian element. II. SCHAACK, C. G., J. T. WITHERSPOON, and T. Bot. Not. 116:409-424. J. WATSON. 1974. In IOPB chromosome MEHRA, P. N. 1976. Cytology of Himalayan number reports XLV. Taxon 23: 619-624. hardwood. Sree Saraswaty Press, Calcutta. SHAW, A. H. K. 1973. A dictionary of the MOORE, D. M. 1967. Chromosome numbers flowering plants and ferns, 8th ed. Cam­ of Falkland Islands angiosperms. Br. Ant­ bridge University Press, Cambridge. arct. Surv. Bull. 14: 69-82. SKOTTSBERG, C. 1922. The phanerogams of MOORE, R. J., ed. 1970-1977. Index to plant the Juan Fernandez Islands. Natural His­ chromosome numbers for 1968-1974. Re­ tory of the Juan Fernandez and Easter gnum Veg. 68: 1-115; 77: 1-112; 84: 1­ Islands 2: 95-240. 134; 91: 1-108; 96: 1-257. ---. 1953. The vegetation of the Juan NEGODI, G. 1935. Reperti cariologici su Fa­ Fernandez Islands. Natural History of the nerogame. Atti Soc. Nat. Mat. Modena Juan Fernandez and Easter Islands 2: 793­ 67:7-9. 960. NORDENSTAM, B. 1977. Senecioneae and Lia­ ---. 1956. Derivation of the flora and beae-Systematic review. Pages 799-830 fauna of Juan Fernandez and Easter Is­ in V. H. Heywood, J. B. Harborne, and B. land. Natural History of the Juan Fernan­ L. Turner, eds. The biology and chemistry of dez and Easter Islands 1: 193-437. the Compositae. Academic Press, London. SKVARLA, J. J., and B. L. TURNER. 1966. ONO, M. Endemism in the flora of the Bonin Pollen wall ultrastructure and its bearing (Ogasawara) Islands with special reference on the systematic position of Blennosper­ to the mode of dispersal. Aliso (in press.) rna and Crocidiurn (Compositae). Am. J. ORNDUFF, R, ed. 1967-1969. Index to plant Bot. 53: 555-563. chromosome numbers for 1965-1967. SMITH, A. C. 1943. The American species Regnum Veg. 50: 1-128; 55: 1-126; 59: 1­ of Drirnys. J. Arnold Arbor. Harv. Univ. 129. 24: 1-33. ORNDUFF, R, P. H. RAVEN, D. W. KYHos, SNOAD, B. 1951. Chromosome numbers of and A. R KRUCKEBERG. 1963. Chromo­ succulent plants. Heredity 5: 279-287. some numbers in Compositae. III. Senecio­ SPELLENBERG, R 1964. In Documented chro­ neae. Am. J. Bot. 50: 131-139. mosome numbers of plants. Madrono 17: PARKER, J. S. 1975. Aneuploidy and isolation 266-268. in two Hypochoeris species. Chromosoma SPOONER, D~ M., T. F. STUESSY, D. J. CRAW­ 52: 89-101. FORD, and MARIO SILVA 0.1987. Chromo­ RAVEN, P. H., and D. W. KYHos. 1965. New some numbers from the flora of the Juan evidence concerning the original basic chro­ Fernandez Islands. II. Rhodora 89: 351­ mosome number of angiosperms. Evolu­ 356. tion 19: 244-248. TURNER, B. L. 1970. Chromosome numbers ROBINSON, H., and R. D. BRETTELL. 1973. in the Compositae. XII. Australian species. Tribal revisions in the Asteraceae. IX. The Am. J. Bot. 57: 382-389. relationship of Ischnea. Phytologia 26: Vos, M. P. DE. 1947. Cytological studies in 153-158. genera of the Mesembryanthemeae. Ann. SANDERS, R W., T. F. STUESSY, and R ROD- Univ. Stellenbosch, Ser. A 25: 1-26.