Eleocharis cryptica Saarela, P.M.Peterson, S.González & D.J.Rosen

  • Authority

    Saarela, Jeffery M., et al. 2010. (Cyperaceae), a dwarf new species from Durango, Mexico. Brittonia. 62 (3): 233-238.

  • Family

    Cyperaceae

  • Scientific Name

    Eleocharis cryptica Saarela, P.M.Peterson, S.González & D.J.Rosen

  • Description

    Description - Plant annual, caespitose; roots fibrous, cream- colored; culms 2- 10(- 13) mm long (as measured to spikelet apex), 0.1-O.2(-0.25) mm wide, (8-) 12-22 per plant, soft, capillary, erect to slightly curved, sometimes twisted, quadrangular- sulcate, often compressed; leaf sheaths some- times grooved adaxially, white to cream-colored proximally, green distally, apex scarious or herbaceous and often extended into a ± appressed, involute, attenuate, light green, punc- ticulate, foliiform prolongation 0.5-3.2 mm long. Spikelets 1.3-1.7x0.8-1.2 mm, 3-6(-7)-flow- ered, ovoid; floral scales 0.8-1.1x0.4-0.5 mm in lateral view, proximal scales fertile, ca. 2/3 the length of the spikelet, polystichous to subdistichous, loosely keeled, membranous, acute, entire, with a green (young) to reddish - brown (matur) mid-vein and broad purple or hyaline margins 0.3mm wide; styles trifid; stamens 1, filametns translucent; anthers ca. 0.25 mm long. Achenes 0.5 - 0.6 (-0.7) mm long (incuding the sytlopodium), 0.3-0.4 mm wide, trigonous, obovoid or broadly ellipsoid, almost smooth to obscurely striolate-reticulated, light olivaceous- brown and somewhat translucent, whitish when immature, the angles prominently white costate, 0.05 mm wide; stylopodium 0.1x0.2 mm near base, pyramidal to depressed-pyramidal, trigonous; bristles absent.

  • Discussion

    Distribution and habitat. - Eleocharis cryptica is known only from a single population (the type locality) located in a private ranch, where it was growing intermittently in gravelly, seasonally-wet grassy flats among open oak- pine forest. The forest was moderately disturbed by some logging and grazing. Because E. cryptica grows in open areas temporarily flooded in which the dominant herbs are very low, it is not likely to be severely affected by the main disturbances. Endemic species are com- mon in the Sierra Madre Occidental and also in Eleocharis, but narrow endemics are rather uncommon in both cases, so additional popula- tions of E. cryptica are expected in similar habitats of the Sierra Madre Occidental. Asso- ciated species at the type locality include Arctostaphylos pungens Kunth (Ericaceae); Bulbostylis funckii (Steud.) C. B. Clarke, B. juncoides (Vahl) Kük. ex Osten, Cyperus bipartitus Torr., C.flavescens L. var.piceus (Liebm.) Fernald, Eleocharis svensoniana S. González, Rhynchospora durangensis Krai & W. W. Thomas (Cyperaceae); Eriocaulon jaliscanum S. Wats. (Eriocaulaceae); Halenia brevicornis (Kunth) G. Don (Gentianaceae); Pinus engelmannii Carrière, P. teocote Schltdl. & Cham. (Pinaceae); Quercus arizonica Sarg., Q. eduar- dii Trel. (Fagaceae); Tagetes micrantha Cav. and Urbinella palmeri Greenm. (Asteraceae).

    Entymology: - The species is named in reference to its dwarf stature and the unknown nature of the foliiform prolongations of its sheaths.

    IUCN Red List Category - Because Eleocharis cryptica is known only from the type location, and there is no data on population trends for the taxon, it therefore can be considered Data Deficient according to the International Union for Conservation of Nature (IUCN) Red List criteria (IUCN, 2001). Additional pipulations of the taxon should be looked for in similar habitats in Durango and adjacent areas.

    We follow the genus - level classification of González Elizondo and Peterson (1997). Eleocharis cryptica is a member of Eleocha- ris subg. Eleocharis sect. Eleocharis ser. Tenuissimae (C. B. Clarke) Svenson, a heter- ogeneous group of more than 50 species characterized by puncticulate culms, usually trigonous achenes that are either nearly smooth or deeply cancellate, and three- branched styles. Two subseries are recog- nized in ser. Tenuissimae: subser. Chaetariae (C. B. Clarke) Svenson (>40 species) and subser. Sulcatae (C. B. Clarke) S. González & P. M. Peterson (>12 species). Eleocharis cryptica belongs to the former group, which is characterized by having low, capillary culms (vs. filiform to more or less coarse), variously colored achenes (vs. whitish to pale-colored) either nearly smooth to deeply cancellate (vs. never deeply cancellate), and sometimes chasmogamous basal spikelets present (vs. not present). Eleocharis cryptica is unusual in the genus in having folliform prolongations of the sheaths that resemble leaf blades more so than do the leaf sheath prolongations rarely observed in other species such as in the E. nigrescens complex and E. subcancellata C. B. Clarke. There are other species that have almost leaf-like projections at the distal end of the upper leaf sheath, such as E. spiralis (Rottb.) Roem. & Schult, and E. kleinii Barros, both of Eleocharis subg. Limnochloa (P. Beauv. ex Lestib.) Torr., and Eleocharis atacamensis Phil., a member of Eleocharis subg. Zinzerlingia T. V. Egorova. It is possible that in E. cryptica these represent a reversal to a well developed lamina, perhaps to provide a greater photosythentic surface area.

    No contemporary treatment of Eleocharis for all of Mexico exists. Thus to identify species that are morphologically similar to E. cryptica, we examined Svenson 's (1937) Eleocharis monograph and multiple treat- ments of Eleocharis for areas in the general vicinity of Durango, Mexico, including Gon- zález Elizondo (1994; Mesoamerica), McVaugh (1993; western Mexico), and Smith et al. (2002; North America north of Mexico). In Svenson's (1937) key to E. ser. Tenuissi- mae, E. cryptica keys to a group of three species with small achenes, including E. nigrescens, E. barrosii Svenson and E. micro- carpa Torr. In Flora Mesoamericana E. cryptica keys to E. urceolata (Liebm.) Sven- son (González Elizondo, 1994). In McVaugh's (1993) flora of western Mexico, it keys to a group of three taxa, including E. subcancellata, E. minima Kunth and E. nigrescens; in Smith et al. (2002) it also keys to E. nigrescens. It is also morphologically similar to E. microlepis (Griseb.) D. A. Simpson and E. setifolia (A. Richard) A. Raynal (Simpson, 1988b). Because of its diminutive size, E. cryptica could be con- fused with the Cuban species E. minutíssima Britton and with the North American species E. uncinalis Chapm. ex Small, the latter considered by Svenson (1937) as a synonym of E. minima but which differs in having polystichous floral scales. A key to separate Eleocharis cryptica from each of these taxa is presented here. (Achene measurements include the stylopodium.)