Selaginella blepharodella Valdespino, 2015

Valdespino, Ivan A., Heringer, Gustavo, Salino, Alexandre, Goes-Neto, Luiz A. de Araujo & Ceballos, Jorge, 2015, Seven new species of Selaginella subg. Stachygynandrum (Selaginellaceae) from Brazil and new synonyms for the genus, PhytoKeys 50, pp. 61-99 : 64-68

Selaginella blepharodella Valdespino sp. nov. Figures 3 , 4 , 5

Diagnosis.

Selaginella blepharodella differs from similar Selaginella thysanophylla A.R. Sm. in its short- (vs. non-) stoloniferous stems, median leaves broadly-ovate to ovate-elliptic (vs. ovate or orbicular), 0.6-1.0 × 0.4-0.6 (vs. 1.4 × 1.0) mm, with stomata on upper surfaces restricted to the midribs (vs. also on submarginal and marginal regions on proximal ¼ near outer bases), lateral leaves broadly ovate to ovate-oblong (vs. ovate or orbicular), 0.8-2.0 × 0.5-0.8 (vs. 2.0 × 1.5) mm, and upper surfaces of sporophylls with long or short cilia along distal ½ of the midribs (vs. upper surfaces glabrous).

Type.

BRAZIL. Bahia: Ibicoara, [13°24'00"S, 41°18'00"W], 26 Aug 2009, P. Moraes & van der Werff 2933 (holotype: PMA!; isotypes: HUEFS-n.v., MO!, UC!).

Description.

Plants terrestrial or epipetric. Stems decumbent to suberect, stramineous, 1.5-9.5 cm long, 0.3-0.4 mm diam., exarticulate, not flagelliform, short-stoloniferous, 1- or 2-branched. Rhizophores axillary or axillary-ventral, restricted to bases of stems, filiform, 0.1-0.2 mm diam. Leaves heteromorphic throughout, chartaceous, those on and above first branch of stems with both surfaces usually glabrous and those below the first branch of stems often with few, caducous cilia-like or dentate projections on the upper surfaces of the median leaves and sporophylls and on the lower surfaces of lateral leaves, upper surfaces green or brownish (when old), lower surfaces silvery green or shiny brown (when old). Lateral leaves imbricate, spreading or ascending, broadly ovate to ovate-oblong, 0.8-2.0 × 0.5-0.8 mm; bases rounded to subcordate, acroscopic bases overlapping stems (more so on leaves below first branch), basiscopic bases free from stems; acroscopic margins broadly hyaline, especially along proximal ⅓ in a band 3-15 cells wide, the cells elongate and papillate parallel to margins, papillae in 1 or 2 rows over each cell lumen, long-ciliate along proximal ⅔ and short-ciliate to serrate along distal ⅓, basiscopic margins hyaline to greenish hyaline in a band 4-6 cells wide, the cells as on acroscopic margins, ciliate throughout or sometimes cilia absent from proximal ¼ -⅓; apices acute, tipped by 1-4 teeth or 2 or 3 cilia, especially on leaves below first branch; upper surfaces comprising quadrangular to rounded, sinuate-walled cells covered by 5-15 papillae, without idioblasts or stomata, lower surfaces comprising elongate, sinuate-walled cells, most of these papillate and idioblast-like, papillae in 1 or 2(-3) rows over each cell lumen, with stomata in 2 or 3(-4) rows along midribs and some along proximal ¼ of basiscopic margins. Median leaves imbricate, ascending, broadly-ovate to ovate-elliptic, 0.6-1.0 × 0.4-0.6 mm; bases oblique, inner bases truncate, outer bases rounded and glabrous or these may also be ventricose (i.e., swollen) and each with a tuft of long cilia on leaves below first branch; margins broadly hyaline, especially the inner ones, in a band 5-15 cells wide, the cells elongate and papillate parallel to margins, papillae in 1 or 2 rows over each cell lumen, long-ciliate throughout or infrequently along only distal ⅘; apices gradually tapering into a long acumen, each acumen 0.1-0.3 mm, tipped by 2 or 3 cilia; both surfaces without idioblasts, upper surfaces comprising quadrangular to rounded, sinuate-walled cells covered by 5-15 papillae, with stomata along midribs, lower surfaces comprising elongate, sinuate-walled cells, without stomata. Axillary leaves similar to lateral leaves. Strobili terminal on branch tips, compact, quadrangular, 1.2-9.0 mm long. Sporophylls monomorphic, without a laminar flap, ovate, 0.6-0.9 × 0.4-0.7 mm, each with a ciliate keel along distal ½ of the midribs; bases rounded; margins hyaline, long-ciliate; apices acute, tipped by 1 or 2 cilia; dorsal sporophylls with upper surfaces green and cells as in median leaves, except for the half that overlaps the ventral sporophylls, there hyaline with elongate, papillate, and slightly sinuate-walled cells, lower surfaces silvery green and comprising elongate, sinuate-walled cells (Fig. 4F ); ventral sporophylls with both surfaces hyaline to greenish, comprising elongate, sinuate-walled cells. Megasporangia in proximal portion in 2 ventral rows; megaspores light-yellow, rugulate-reticulate on proximal faces, reticulate on distal faces, with psilate-perforate microstructure on both faces, 200-230 μm diam. Microsporangia in 2 dorsal rows and, in distal portion, also in 2 ventral rows; microspores orange, verrucate-rugulate with granulate microstructure on proximal faces, broadly capitate to clavate (5B-D) or broadly baculate (if apices of projected elements broken off, Fig. 5G, H ) with reticulate-perforate and echinulate microstructure on distal faces, ca. 30-38 μm diam.

Habitat and distribution.

Selaginella blepharodella is presumed to be a local endemic of the Serra do Sincorá, Espinhaço Range, state of Bahia, Brazil, where it is known from only two localities, growing on sandy soil or overhanging from rocks at 1400 m.

Etymology.

The epithet of the new species derives from the Greek blepharis, meaning eyelash, ode meaning similar to and ella, Latin diminutive suffix; this refers to the long-ciliate leaf margins that resemble miniature eyelashes.

Conservation status.

Selaginella blepharodella is known from only two collections in Serra do Sincorá and may be expected to occur in places with similar vegetation types in the Chapada Diamantina region of the Espinhaço Mountain Range. The Chapada Diamantina region and the Espinhaço Mountain Range, in general, are still subject to anthropomorphic pressure, including low-scale mining ( Pedreira 2002), subsistence agriculture accompanied by the slash-and-burn methods, and plant extraction for commerce ( Rapini et al. 2008). Based on these threats and according to IUCN (2012) categories and criteria, this species is tentatively considered vulnerable (VU).

Additional specimen examined (paratype).

BRAZIL. Bahia: Serra do Sincorá, 1400 m, Nov 1906, Ule 7298 (B, BM, PMA-fragment).

Discussion.

Selaginella blepharodella is a member of subg. Stachygynandrum and is defined here in a broad sense to encompass the morphological variability found within the two collections examined. In general, this species is characterized by long-ciliate leaves with broadly hyaline margins, lateral leaves imbricate, spreading to ascending with lower surfaces almost completely comprising elongate, papillate, sinuate-walled cells with papillae in 1-3 rows over cell lumina and stomata in 2 or 3(-4) rows along midribs amidst shortly elongate, sinuate-walled cells, and median leaves with apices ending in 2 or 3 cilia (Figs 3 , 4 ). The type collection (Moraes & van der Werff 2933) has stems more than 3 cm tall, is 2- or 3-brached, and has lateral leaves mostly spreading to ascending and imbricate at branch tips (Fig. 3 ), whereas the paratype (Ule 7298) is a much smaller plant to 3 cm tall, is 1- or 2-branched, and has lateral leaves imbricate throughout (Fig. 4 ). In both specimens, the leaves below the first branch tend to be more imbricate, have wider hyaline margins and longer marginal cilia, and the outer bases of the median leaves may be ventricose and with a tuft of long cilia (Fig. 4E ). Additionally, below the first branch, they may have scarce and caducous cilia-like projections on the upper surfaces of the median leaves and sporophylls (Fig. 4E, F ) and on the lower surfaces of lateral leaves. In these characters, Selaginella blepharodella , especially the paratype, is similar and perhaps related to Selaginella thysanophylla from Venezuela (Fig. 4G ). These two species also share similar megaspore color; however Selaginella blepharodella can be separated from Selaginella thysanophylla by the characters discussed in the diagnosis. Selaginella blepharodella differs further from Selaginella thysanophylla by having megaspores 200-230 (vs. 150-200) μm, lateral leaves with acute (vs. rounded to subacute) apices, median leaves with the inner margins hyaline in a band 5-15 (vs. 20-25) cells wide at least along proximal ⅓ with long-acuminate (vs. apiculate) apices, each acumen 0.1-0.3 (vs. acumen 0.05-0.1) mm, and sporophyll apices each tipped by 2 cilia (Fig. 4F ) [vs. 2 teeth; (Fig. 4H )].

In Brazil, Selaginella blepharodella does not seem to have close relatives, but it shares some characters, e.g., hyaline and ciliate leaf margins, with the newly described Selaginella mucugensis and Selaginella crinita (which see for comparison).

Figures

Figure 3. Selaginella blepharodella Valdespino. A Section of upper surface of stem B Upper surface of median leaf C Section of lower surface of stem D Lower surface of lateral leaf E Megaspore proximal face F Close-up of megaspore proximal face surface G Megaspore distal face H Close-up of megaspore distal face surface A-D taken from holotype, Moraes & van der Werff 2933 (PMA) E-H taken from paratype, Ule 7298 (B).

Figure 4. Selaginella blepharodella Valdespino. A Section of upper surface of stem B Upper surface of median leaf C Section of lower surface of stem D Lower surface of lateral leaf E Upper surface of median leaf, note: cilium-like or tooth projection (a) and long cilia on outer base (b) F Upper surface of dorsal sporophyll, note: cilia-like or teeth projections on distal portion of midrib (a) A-F taken from paratype Ule 7298 (B). Selaginella thysanophylla A. R. Sm. G Upper surface of median leaf, note: stomata on submarginal and marginal regions on proximal 1 / 4 near outer base (a) and outer base tufted with long cilia (b) H Upper surface of ventral sporophyll G, H taken from Steyermark et al. 113322 (NY).

Figure 5. Selaginella blepharodella Valdespino. A Microspore proximal face B Microspore equatorial view C Microspore distal face D Close-up of microspore distal face surface E Microspore proximal-equatorial view F Close-up of microspore proximal face surface G Microspore distal face H Close-up of microspore distal face surface A-H taken from holotype, Moraes & van der Werff 2933 (PMA).