Great Basin Naturalist

Volume 41 Number 1 Article 6

3-31-1981

Eriogonum divaricatum Hook (), an intermountain in Argentina

James L. Reveal University of Maryland, College Park, and Smithsonian Institutuion, Washington, D.C.

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Recommended Citation Reveal, James L. (1981) "Eriogonum divaricatum Hook (Polygonaceae), an intermountain species in Argentina," Great Basin Naturalist: Vol. 41 : No. 1 , Article 6. Available at: https://scholarsarchive.byu.edu/gbn/vol41/iss1/6

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. ERIOGONUM DIVARICATUM HOOK. (POLYGONACEAE), AN INTERMOUNTAIN SPECIES IN ARGENTINA

James L. Reveal'

Abstract.— Erogonum divaricatum, an annual herb of clay slopes and flats in the Green and Colorado river drain- age basin of the western United States, was found at the turn of the century in three locations in southern Argentina. The South American material was described in 1902 as a new species of Erogonum, E. ameghinoi Speg., and this name was the basionym for a new monotypic , Sanmartinia M. Buchinger, proposed in 1950. The species has not been rediscovered in Argentina, and the presence of the species in South America was probably the result of a long-distance dispersal event involving shore birds.

With the pubUcation of Eriogonum ameg- cases, the migration was a success and coloni- hinoi Speg. (Spegazzini 1902), Eriogonum zation occurred. Michx. (Polygonaceae), long considered re- My own views regarding Sanm.artinia have stricted to Canada, United States, and Mexi- been largely masked in ignorance of the co, became defined as a taxon found in both exact nature of the material. In my doctoral North and South America. When Buchinger dissertation (Reveal 1969), Eriogonum ameg- (1950) based the monotypic Sanmartinia on hinoi was excluded from the genus and E. ameghinoi, Eriogonum was once again de- placed in Sanmartinia. This view persisted fined as endemic to North America. Other until publication of the excellent paper by genera belonging to the subfamily Eriogo- Moreau and Crespo (1969). They noted that noideae are present in Chile and Argentina, the supposed lack of an involucre, as sug- namely Clwrizanthe R. Br. ex Benth. (Good- gested by I. M. Johnston on an annotation at- man 1934), Oxytheca Nutt. (Ertter 1980), and tached to one of the Ameghino specimens, Lastarriaea Remy (Goodman 1934). All are badly misled Buchinger, and the species was related to Eriogonum but differ in having not representative of a new genus but a typi- barbed or otherwise armed involucres or tep- cal species of Eriogonum. als. This morphological feature has been sug- Unfortunately, Moreau and Crespo had ac- gested as the means for dispersal by animals cess only to Abrams (1944) as a means of from arid regions in western North America comparison of the Argentinan material with T. Howell to similar areas in southern South America North American species. When J. (Reveal 1978). I have proposed (Reveal 1978) of the California Academy of Sciences called two separate occasions of migration. The first my attention to their paper in 1970, I came involved the perennial species of Chorizanthe to the conclusion, based on their illustration now found in South America that came from (as well as Buchinger's plate) that E. ameg- the then perennial members of the genus in hinoi was probably a synonym of E. divarica- North America (now extinct in the north and tum Hook. This point was reinforced by replaced by annual species). The second mi- Moreau and Crespo's observation that a five- gration that occurred probably happened parted involucre was present as Spegazzini much later (probably during the Pleistocene), (1902) had stated, and not lacking as Johnston and this resulted in the introduction of an ar- had implied. ray of annual species into South America, no- Eriogonum divaricatum is an annual herb tably O. dendroidea Nutt. ssp. chiliensis found often on gumbo clay hills and flats in (Remy) Ertter, C. commissuralis Remy, and the Colorado and Green river drainage basin probably L. chiliensis Remy. In each of these of southwestern Wyoming southward

'Department of Botany, University of Maryland, College Park, Maryland 20742, and National Museum of Natural History, Smithsonian Institution, Wash- ington, D.C. 20560. Work on this study has been supported by National Science Foundation Grant BMS75- 13063. This is Scientific Article A2724, Contribu- tion No. 5772, Maryland Agricultural Experiment Station, Department of Botany.

143 144 Great Basin Naturalist Vol. 41, No. 1 through eastern Utah and adjacent western unique events that have not been sub- Colorado into northwestern New Mexico and sequently repeated. northern Arizona (Reveal 1973, 1976). It is Eriogonum divaricatum occurs in heavy also on the northern shore of Sevier Lake, clay soil that tends to clump when wetted. In Millard Co., western Utah {Reveal ir Reveal some years in eastern Utah, great masses of 4001). This reduction of Sanmartinia and E. annual Eriogonum species will be found in arneghinoi to E. divaricatum was suggested flower. This is particularly true of E. in- by Reveal and Howell (1976) in the key to flatum Torr. & Frem. var. fusiforme (Small) genera of the subfamily Eriogonoideae and Reveal, but will occasionally happen in such later repeated in more detail in a review of species as E. scahrellum Reveal, E. suh- the subfamily (Reveal 1978); however, in reniforme S. Wats., E. wetherillii Eastw., both both instances this was done based solely species of the genus Stenogonum Nutt. (see upon observations of illustrations and not the Reveal and Ertter 1977), and even E. diva- actual examination of the specimens. ricatum. Unlike most of these species, E.

Two of the collections of Eriogonum arneg- divaricatum is in full fruit during the early hinoi (both at LP) have been made available fall of the year. By this time the other an- for study (a third is at BA, fide Moreau and nuals have dropped their seeds, or, in the Crespo [1969]). These two specimens were case of E. scahrellum, will not be in full fruit Ameghino 11317 from Lago Colhue-Huapi, until late in the fall. Dpto. Sarmiento, Chubut, Argentina, gath- The distribution of Eriogonum divaricatum ered in 1900, and Ameghino 11318 from be- is relatively widespread in the Intermountain tween San Julian and Rio Deseado, collected West, occurring, as noted above, from in 1899. The first collection, the more mature Wyoming to New Mexico and Arizona. of the two, and the one on which Spegazzini Within such a large area it would normally

(1902) based his description, is here selected be difficult to determine where the South as the lectotype for the species. The nearly American came from were it not for complete specimen in the upper left-hand minor populational differences in the floral corner of the lectotype served as the basis for hair morphology associated with the tepals of the illustration in both Buchinger (1950) and E. divaricatum. The hairs of the South Amer- Moreau and Crespo (1969). This collection ican plants are long, slender, smooth, and was gathered near a large, inland lake lo- pointed at the tip on mature tepals. The hairs cated west-northwest of Comodoro Rivadavia on tepals from plants gathered in northern in southeastern Chubut. The second collec- Arizona, western Utah, and southeastern tion came from an imknown location some- Utah are short, bulbous apically, smooth, and where between Rio Deseado and San Julian. rounded at the tip. Hairs of other plants This is an arid region dotted with occasional gathered in northern Arizona and eastern lakes, but the distance between the two refer- Utah are similar to those of the South Ameri- ence points is nearly 300 km, and it is impos- can plants except that the shaft of the hair is sible to determine where the collection was slightly papillose and not smooth. An exam- made. The third specimen (not seen by me) ination of floral hairs from plants gathered in was gathered at Deseado, a small town on scattered portions of northeastern Arizona the Atlantic coast near the mouth of Rio De- most closely resemble the hairs of the South seado. The last two collections came from American , with those found on an East- eastern Santa Cruz. wood and Howell collection (6497-US) gath- In the intervening years Eriogonum diva- ered near Cameron, Cocconino Co., being ricatum has not been recollected in South the most similar.

America. That it was relatively widespread is Because Eriogonum divaricatum is com- shown by the three separate sites where it mon along major waterways in this part of was collected, a distance of perhaps 400 km Arizona, and elsewhere in its range, and these north-south. Although it is likely that Ameg- waterways are heavily visited by migratory hino selectively collected sites where the birds, I suspect that the introduction of E. Eriogonum might be foimd, that he found it divaricatum into portions of Argentina lo- and no one else has may be due to a series of cated precisely at the southern end of a March 1981 Reveal: Eriogonum Divaricatum in Argentina 145

major north-south flyway (see National Geo- the introduction of E. divaricatum occurred graphic Map, "Bird Migration in the Ameri- during the Quaternary, I cannot state for cer- cas," Aug. 1979) was accomphshed by migra- tain when. If the plants persisted for only a

ting birds. It is unlikely that seeds of the few years after their initial introduction, and Eriogonum were eaten but not digested and during one of the growing seasons Ameghino collections, passed in a viable ?tate. Rather, it is more found them and made then the likely that seeds were attached to birds, prob- species might never have truly become estab- ably on mud-caked feathers, and carried pas- lished. If the species was extirpated naturally after the plants, sively to South America. Only a few groups Ameghino collected the events associated with the extirpation will of birds have this extended pattern of distri- never be ascertained. If the buckwheat was bution, and one of them is the shore bird. Of recentlv introduced, as a result of a one- the several species that are found in the In- chance event, then its extirpation might have termountain West, e.g., Bartramia longicauda been just as sudden. (Upland Plover), Tringa solitaria cinnamoma (Western Solitary Sandpiper), and Tetanus flavipes (Yellow-legs), among others (Bailey Acknowledgments 1928, Hayward et al. 1977), only one, To- I thank Dr. Angel L. Cabrera and the staff tanus flavipes, is common throughout the at the Facultad de Ciencias Naturales area where the Eriogonum occurs in Argen- y Museo, Universidad Nacional de La Plata, for tina (Olrog 1968). Interestingly, this species, making the specimens of Eriogonum ameg- as with other shore birds, is capable of flying hinoi available, and Dr. W. Aldrich, De- the entire distance from Utah and Arizona to J. partment of Ornithology, National Museum South America nonstop W. Aldrich, pers. (J. of Natural History, Smithsonian Institution, comm.). Washington, D.C., for his help with deter- Why Eriogonum divaricatum has not been mining bird species that might be responsible recollected in Argentina cannot be deter- for the distribution of Eriogonum in South mined, but that fact alone should not exclude America. Dr. John L. Strother kindly re- the possibility that the species is not still ex- viewed and commented upon a draft of the If extirpated, however, tant in the country. manuscript. some consideration can be given to the in- troduction of E. divaricatum into Argentina Cited as a single, imique event. If there was a large Literature population of E. divaricatum, say in north- Abrams, L. 1944. Ilhistrated flora of the Pacific states. eastern Arizona, that was fed upon at the Vol. 2. Stanford: Stanford University Press. same time by numerous birds, and by some Bailey, F. M. 1928. Birds of New Mexico. Washington, Detweiler, Inc. remarkable event seeds ended up in Argen- D.C.: Judd & BucHiNGER, M. 1950. Sanmartinia, nnevo genero patago- tina in different places, germinated, and grew nico de Poligonaceas. Coniun. Inst. Nac. Invest. and plants were fortuitously collected by a Ci. Nat., Ser. Ci. Bot. 1(4):3-13. that B. 1980. revision of the genus Oxytheca botanist during the one growing season Ertter, J. A the plants were extant, this would have been Nutt. (Polygonaceae). Brittonia 32:70-102. Goodman, G. 19.34. A revision of the North American astonishing. J. species of the genus Chorizanthe. Ann. Missouri It is possible that divaricatum Eriogonum Bot. Gard. 21:1-102. persisted in Argentina for several thousands Grant, V. 1967. The selective origin of incompatibility of years. The floral hair differences are ad- barriers in the plant genus Gilia. Amer. Natural- ist 100:99-118. mittedly slight but do indicate a slight degree Hayward, G. L., C. Cottam, A. M. Woodbury, and H. of divergency that could be associated with H. Frost. 1977. Birds of Utah. Great Basin Nat. isolation (see Grant [1967] for an example in Mem. 1:1-229. Gilia). The length of time that that divergen- MoREAU, R. L. P., AND S. Crespo. 1969. Rehabilitacion ameghinoi Speg. caida en sino- cy may have had to develop is another mat- de Eriogonum y nimia del genero Sanmartinia (Polygonaceae). ter. As Raven (1963) has pointed out, the tim- Darwiniana 15:112-114. ing of the events into various migration Olrog, C. C. 1968. Las Aves Sudamericanas usa guia de South America from North America is still Gampo. Tucuman: Universidad Nacional de Tu- confusing, and, though I feel (Reveal 1978) cuman. 146 Great Basin Naturalist Vol. 41, No. 1

1978. Distribution phylogeny of Raven, P. H. 1963. Amphitropical relationships in the and Eriogo- floras of North and South America. Quart. Rev. noideae (Polygonaceae). Great Basin Nat. Mem. 2:169-190. Biol. 38:151-177. Reveal, L., and B. Ertter. 1977. Re-establishment Reveal, L. 1969. A revision of the genus Eriogonum J. J. J. of Stenogonum (Polygonaceae). Great Basin Nat. (Polygonaceae). Provo, Utah: Unpublished doc- 36:272-80. toral dissertation, Brigham Young University Li- L., Reveal, J. and J. T. Howell. 1976. Dedeckera (Po- brary. lygonaceae), a new genus from California. Brit- 1973. Eriogonum (Polygonaceae) of Utah. Phyto- tonia 28:245-251. logia 25:169-217. Spegazzini, C. 1902. Nova addenda ad floram patagoni- 1976. Eriogonum (Polygonaceae) of Arizona and cam. (Pars III). Anales Mus. Nac. Hist. Nat. New Mexico. Phytologia 34:409-484. Buenos Aires 7:135-203.