Selaginella surucucusensis L.A.Góes & E.L.M.Assis

de Araújo Góes-Neto, L.A. et al. 2017. Selaginella (Selaginellaceae) from Brazil: a new species, new records and lectotype designation. Kew Bulletin 72:40. DOI 10.1007/S12225-017-9714-5

Type

Type: Brazil, Territorio Federal de Roraima [Rorai- ma]: Serra Surucucu [Serra dos Surucucus], 26 Jan. 1975, B. G. S. Ribeiro 616 (holotype HRB [HRB 7465]!; isotypes BHCB [BHCB 184775]!; HRB [HRB 12734]!; RB [RB 173616]!).

Morphology General Habit

Plants terrestrial

Morphology Stem

Stems decumbent to erect, stramineous to slightly greenish, 35 - 45 cm long, 1.2 - 2.0 mm diam., not articulate, not flagelliform, stoloniferous or not, 2 (- 3)- branched

Morphology Branches

Rhizophores ventral, dorsal or lateral, filiform to stout, restricted to the underground portion

Morphology Leaves

Axillary microphylls ovate-oblong to oblong, bases rounded; margins finely serrulate throughout; apices obtuse; both surfaces similar to the lateral microphylls Dorsal microphylls usually imbricate, rarely distant, ascending, elliptic to nearly obovate, 1.5 - 3.0 x 1.0 - 1.5 (- 2) mm; bases oblique with a slightly developed outer denticulate auricle; margins narrowly hyaline, finely serrulate throughout; apices acuminate or less frequently slightly attenuate; upper surfaces with several papillate cells mainly in outer half, without idioblasts and with 2 – 3 rows of stomata along midribs Lateral microphylls distant to slightly imbricate, perpendicular to slightly ascending, ovate-oblong to oblong, 3.0 - 4.0 x 1.2 - 1.8 mm; bases rounded to occasionally truncate, acroscopic base overlapping the stem, basiscopic base not overlapping the stem; acroscopic margins narrowly hyaline especially in basal =13, finely serrulate throughout, basiscopic margins greenish to narrowly stramineous, entire throughout; apices obtuse; upper surfaces with several papillate cells mainly in apical ½, without idioblasts and stomata; lower surfaces with papillate cells, occasionally with scattered idioblasts and with three rows of stomata along midribs Microphylls on main stems isomorphic and appressed, at least up to shortly below the first branch, heteromorphic above the first branch, slightly coriaceous, both surfaces glabrous, upper surfaces smooth, shiny, olive green, lower surfaces smooth, pale green

Note

Selaginella surucucusensis is similar to S. amazonica Spring and S. palmiformis Alston ex Crabbe & Jermy, but, differs chiefly from both by having lateral microphylls with obtuse and straight (vs acute and slightly falcate) apices. Named for its type location, Serra dos Surucucus, in Roraima State, Brazil. All specimens examined are sterile; however, this species has the main stem unusually long, and the upper surfaces of microphylls with several papillate cells, characters facilitating recognition of the species. Selaginella surucucusensis differs from S. amazonica by its lateral microphylls ovate-oblong to oblong (vs ovate- deltate to ovate-oblong), bases usually rounded (vs truncate to slightly asymmetric); dorsal microphylls elliptic or approaching obovate (vs ovate to ovate- deltate); axillary microphylls ovate-oblong to oblong (vs ovate-deltate), bases rounded (vs truncate), apices obtuse (vs acute); main stems terete (vs tetragonal) just below the first branch; and plants olive green (vs brown to dark brown) when dry. It differs from S. palmiformis by its lateral microphylls ovate-oblong to oblong (vs oblong to oblong-lanceolate); axillary microphylls with margins finely serrulate throughout (vs serrate in basal % and serrulate near the apex), apices obtuse (vs acute); and stems 2 (- 3)-branched (vs 1-branched).

Distribution

This species is known only from Rorai- ma State, Brazil; it is possible that it occurs in other northern Brazilian states (e.g., Amazonas) and may also occur in southeastern Venezuela.

Ecology

Terrestrial, growing on river­banks at 1000 - 1400 m.

Conservation

Selaginella surucucusensis is known only from seven specimens (type collection) collected at a single or proximate localities. No details are known about the number of plants or extent of the population(s), but we speculate that the species also occurs in other places in Roraima State, possibly in Venezuela as well. For these reasons this species should be classified as Data Deficient (DD) within IUCN (2012) guidelines.