Plaubelia khasiana Asthana and Srivastava

Asthana, A. K. & Srivastava, Ankita, 2018, A new species of Plaubelia Bridel (Pottiaceae, Bryophyta) from India, Phytotaxa 374 (4), pp. 297-300 : 297-299

Plaubelia khasiana Asthana and Srivastava ( Figure 1 )

Diagnosis: Plants rosulate with innovating young shoots from rosulate apices, 3–5 mm long leaves appressed falcate when moist, upper leaves larger than the lower leaves, spathulate to oblong, broad at middle, leaf apex subacute to apiculate with crenulate margin from apex to base, costa ending below apex, in cross section costa with 4 guide cells in centre. bulging adaxially, oval or round gemmae (40–60μm) present.

Type: India, Meghalaya: Wards lake, Shillong, alt. ca. 1402 m, on brick wall, 21.9.2015, A. Srivastava 300333 C (Holotype: LWG).

Plants small forming loose turf, green above brown below. Young shoots innovated from rosulate apices at definite intervals and each segment is rosulate. Stem short 3–5mm long, nearly rounded in cross section, central strand present, in cross section of stem hylodermis absent, sclerodermis of large rounded to subrectangular cells ±7–14μm × 7μm, axillary hyaline hairs not seen. Leaves appressed to weakly spreading, falcate when moist, spathulate to oblong, narrower at base, upper leaves larger (0.6–0.9mm) as compared to lower leaves (0.2–0.3mm), broad at middle (0.2–0.3mm), leaf apex sub-acute to apiculate with crenulate margin from apex to base, margin incurved or involute from apex to middle; costa ending usually 6 cells below apex, in cross section rounded with one stereid band on abaxial surface, guide cells 4 in one layer in the centre, bulging on adaxial surface, blade cells rounded, ± 7.1μm × 5.7μm, surface of blade crenulate, apical & middle cells of leaf rounded to hexagonal 6μm × 6μm thick walled, basal cells quadrate-sub-rectangular 12–18μm × 9–12μm, thick walled; gemmae borne in leaf axils, round to oval, 40–60μm. Sporophyte not seen.

Ecology or Habitat:— Plants were growing on a brick wall at Shillong (Wards lake), Khasi hills (Meghalaya) at an altitude of 1402m.

Etymology:— The species epithet refers to the Khasi hills from where the specimens were collected. The Khasi hills area is very important and bryologically rich area of Meghalaya State.

Figures

FIGURE 1. Plaubelia khasiana sp. nov. 1. Plant. 2. Cross section of stem. 3–8 Leaves. 9–12. Gemmae. 13. Cross section of leaf. 14, 15. Leaf apex. 16. Median cells of leaf. 17. Juxta costal cells in leaf. 18. Basal marginal cells of leaf.