Selaginella nanuzae Valdespino, 2015

Valdespino, Ivan A., 2015, Novelties in Selaginella (Selaginellaceae - Lycopodiophyta), with emphasis on Brazilian species, PhytoKeys 57, pp. 93-133 : 95-96

Selaginella nanuzae Valdespino sp. nov. Figures 1 , 2 , 3

Diagnosis.

Selaginella nanuzae differs from typical Selaginella contigua Baker by its coriaceous (vs. chartaceous) leaves with the upper surfaces shiny and bumpy (vs. dull and smooth to slightly corrugate), the acroscopic margins of the lateral leaves and both margins of the median and axillary leaves broadly (vs. faintly) hyaline, median leaves with long-aristate (vs. acute to short-acuminate) apices, each arista 0.4-0.6 mm (vs. acumen 0.05-0.2 mm), midribs straight (vs. arcuate) with the outer bases auriculate (vs. lacking auricles) and bearing10-18 long-cilia (vs. outer bases ciliate with 2-5 cilia), and the lateral leaves 2.5-3.0 × 1.0-1.5 mm (vs. 7.0-10 × 2.0-2.7 mm).

Type.

BRAZIL. São Paulo: [Mpio.] Ubatuba, Parque Estadual da Serra do Mar, Núcleo Picinguaba, trail to Pico Corcovado, 23°26'56.6"S, 45°11'35.8"W, 450 m, 1 Nov 2001, A. Salino, V.A.O. Dittrich, P.O. Morais, F.A. Carvalho, L.C.R.S. Teixeira & A.M. Oliveira 7788 (holotype: PMA! [PMA103268]; isotype: BHCB [BHCB65041]-n.v.).

Description.

Plants terrestrial. Stems decumbent to ascending or suberect, stramineous, 3-5 cm long, 0.5-1.0 mm diam., non-articulate, not flagelliform or stoloniferous, 2-3-branched. Rhizophores ventral or ventro-axillary, borne on proximal ½ of stems, stout, 0.5-1.0 mm diam. Leaves heteromorphic throughout, coriaceous, strongly imbricate, upper surfaces bumpy and green, lower surfaces corrugate to striate and silvery green. Lateral leaves ascending, ovate-oblong or ovate, 1.5-3.0 × 0.9-1.5 mm; bases rounded to semicordate, acroscopic bases strongly overlapping stems, basiscopic bases free from stems; acroscopic margins broadly hyaline in a band 5-10 cells wide with the cells elongate, straight-walled and papillate parallel to margins, papillae in 1 row over each cell lumen, long-ciliate along proximal ¾, otherwise denticulate distally, basiscopic margins greenish, comprising quadrangular, sinuate-walled, glabrous and papillate cells, long-ciliate along proximal ⅛, otherwise entire distally or denticulate on distal ⅛; apices falcate and acute or gradually tapering and acute, variously tipped by 1-3 teeth; upper surfaces comprising quadrangular or rounded, sinuate-walled cells (often difficult to distinguish because of waxy deposits), many of these covered by 6-40 papillae, without idioblasts or stomata, lower surfaces comprising elongate, sinuate-walled cells, with many of these papillate and idioblast-like on both side of the midribs (more so on acroscopic halves of the laminae), papillae in 1-3 rows (or rows not clearly distinguishable) over each cell lumen, with stomata in 2-5 rows along midribs and along distal ⅙ of basiscopic margins. Median leaves ascending, ovate to ovate-elliptic or orbicular, 1.2-1.8 × 0.6-1.2 mm; bases truncate or oblique with outer bases auriculate, auriculae tufted with 10-18 cilia; margins broadly hyaline in a band 2-8 cells wide, the cells elongate, straight-walled and papillate parallel to margins, papillae in 1 row over each cell lumen, long-ciliate throughout and more obviously so on outer margins (cilia on outer margins half to one time longer than the inner cilia); apices long-aristate, each arista ⅓- ½ the length of the laminae (0.4-0.9 mm), variously tipped by 1-3 teeth; both surfaces without conspicuous idioblasts, upper surfaces comprising quadrangular, rectangular or rounded, sinuate-walled cells (often difficult to distinguish because of waxy deposits), many of these covered by 7-25 papillae, with stomata in 2-5 rows along distal ½ of the midribs, few on submarginal portion along proximal ⅕ of outer halves of the laminae, lower surfaces comprising elongate, sinuate-walled cells, without stomata. Axillary leaves ovate or ovate-lanceolate, 1.5-2.6 × 0.8-1.1 mm; bases rounded; margins broadly hyaline, long-ciliate along proximal ⅓, short-ciliate on central ⅓, otherwise dentate on distal ⅓; apices acute to broadly acute, variously tipped by 1-3 teeth; both surfaces as in lateral leaves. Strobili terminal on main stem and branch tips, loosely quadrangular, 0.4-1.6 cm. Sporophylls monomorphic, without a laminar flap, each with a strongly developed and seemingly glabrous keel along midribs, broadly ovate to ovate-deltate, 1.0-1.2 × 0.6-1.1 mm; bases truncate; margins broadly hyaline, dentate to short-ciliate; apices short-acuminate to cuspidate, each acumen (cusp) 0.1-0.2 mm, tipped by 1-3 teeth; dorsal sporophylls with upper surfaces green and cells as in median leaves, lower surfaces silvery green and comprising elongate, sinuate-walled cells; ventral sporophylls with both surfaces hyaline or greenish hyaline, comprising elongate, sinuate-walled cells. Megasporangia in 2 ventral rows; megaspores yellow, rugulate-reticulate on proximal faces with verrucate, perforate, and echinulate microstructure, reticulate on distal faces with verrucate and perforate microstructure (Fig. 3A-D ), 260-355 µm. Microsporangia in 2 dorsal rows; microspores orange, rugulate on proximal faces with echinulate microstructure, capitate or clavate on distal faces with each caput and the rest of the surface with echinulate microstructure (Fig. 3E, F ), 25-30 µm.

Habitat and distribution.

Selaginella nanuzae grows in dense premontane wet forests at 450 m in Atlantic forest vegetation. It is known only along the trail to Morro Corcovado in Parque Estadual da Serra do Mar, São Paulo.

Etymology.

This species is named for Professor, Dra. Nanuza Luiza de Menezes, an outstanding Brazilian botanist, who has been instrumental in advancing botanical and conservation sciences in her country and, in the course of her career, has mentored new generations of botanists at the University of São Paulo. Through her involvement with the Latin American Botanical Association, in 1992, I attended a plant morphology and anatomy course with emphases in taxonomy and evolution at that University; this led to my first exposure to, and study of, Brazilian Selaginella .

Conservation status.

Selaginella nanuzae was collected in a state park, where it may be adequately conserved. Nevertheless, given that there is large visitation along the trails of this park, particularly to ascend to Morro Corcovado where the only two known collections of the new taxa were made, and that some degree of deforestation occurs there, it is considered Vulnerable (VU).

Additional specimen examined

(paratype). BRAZIL. São Paulo: Mpio. Ubatuba, Morro Corcovado, 8 Sep 1998, Ribas & Dittrich 2729 (NY).

Discussion.

Selaginella nanuzae is characterized by the upper surfaces of the leaves shiny (due to waxy deposits) and bumpy (Figs 1 , 2 ), the median leaves long-aristate (Fig. 1A, B, E, F ), the acroscopic margins of the lateral leaves (Fig. 2B-D, E, G ) and both margins of the axillary and median leaves (Fig. 1B-D, F-H ) broadly hyaline, as well as the apices of the lateral leaves acute (Fig. 1A, E ; Fig. 2A, B, E, G ).

The two specimens cited here under Selaginella nanuzae were previously determined as Selaginella contigua , which as currently circumscribed is a morphologically variable species needing additional study. Selaginella nanuzae differs from typical Selaginella contigua , as lectotypified by Hirai and Prado (2000), by the characters given in the diagnosis. Selaginella nanuzae further differs from Selaginella contigua by its ovate-oblong or ovate (vs. oblong) lateral leaves with the apices acute (vs. truncate or broadly obtuse), and ovate or ovate-lanceolate (vs. ovate-lanceolate) axillary leaves with rounded bases (vs. rounded to cordate). In addition, Selaginella nanuzae has strongly imbricate leaves, while Selaginella contigua has leaves that are usually distant.

Figures

Figure 1. Selaginella nanuzae Valdespino. A Section of upper surface of stem B Upper surface of median leaf C Close-up of base and proximal portion of median leaf, upper surface; note marginal (a) and submarginal (b) stoma, and outer base tufted with long cilia (c) D Close-up of distal portion and apex of median leaf, upper surface E Section of upper surface of stem F Close-up of outer half of median leaf, upper surface G Close-up-of inner half of median leaf, upper surface H Lower surface of median leaf. A-H taken from the holotype, Salino et al. 7788 (PMA).

Figure 2. Selaginella nanuzae Valdespino. A Section of lower surface of stem B Lower surface of lateral leaf C Close-up of base and distal portion of lateral leaf, lower surface D Close-up of acroscopic half of lateral leaf near base, lower surface E Close-up of distal portion and apex of lateral leaf, lower surface F Close-up of portion of basiscopic margin of lateral leaf near apex, lower surface; note marginal stoma (a) G Upper surface of lateral leaf H Close-up of upper surface of lateral leaf. A-H taken from the holotype, Salino et al. 7788 (PMA).

Figure 3. Selaginella nanuzae Valdespino. A Megaspore, proximal face B Close-up of megaspore, proximal face C Megaspore, distal face D Close-up of megaspore, distal face E Microspore, proximal face F Microspore, distal face. A-F taken from the holotype, Salino et al. 7788 (PMA).