Peliosanthes khasiana N.Tanaka, 2018

Tanaka, Noriyuki, 2018, Taxonomic revision of Peliosanthes bakeri and P. violacea (Asparagaceae), with description of two new species from Bangladesh and India, Phytotaxa 356 (1), pp. 34-48 : 38-39

2. Peliosanthes khasiana N.Tanaka , sp. nov. ( Figs. 1–3 ).

Close to P. violacea , but distinguishable by the smaller leaf blades with fewer longitudinal veins, shorter pedicels, dark bluish or greyish leaden perigones, slightly larger anthers, style with 3 narrow intercarpellary (septal) wings, and slightly larger stigmas.

Type:― INDIA. Khasia: Cachar, 0–4000 ft, regio. trop., 28 November 1850, J.D. Hooker & T. Thomson s.n. (holotype K-000099355!– lectoparatype of P. violacea var. violacea , p.p, as to the right individual, excluding the left large leaf. Isotype (without record of collection date and locality “Cachar”):―K-000099366!–lectoparatype of P. violacea var. violacea ; L-1449929*!–isolectoparatype of P. violacea var. violacea ; U.1213309*! (in L)–isolectoparatype of P. violacea var. violacea .

Peliosanthes violace a Wallich ex Baker var. minor Baker (1879: 504) , p.p.

Peliosanthes violacea Wallich ex Baker var. violacea Baker (1879: 504) , p.p.

Herb acaulescent, evergreen, perennial. Rhizome ascending to erect, subterete, to 5 cm long, to 1 cm in diam., knobby, often shortly branched, distally covered with scarious fibrous remnants of scaly, sheath leaves. Roots cordlike, to 2 mm in diam. Sheath leaves (cataphylls) a few at base of foliar petiole, unequal in length, imbricate, inner longer ones narrowly lanceolate or ensiform, to 6 cm long, 0.5 cm wide, withering into dry fibrous remnants. Leaves 4–12(–19), basal, fastigiate, erect to obliquely spreading; petiole subterete, 7–26 cm long, 1.2–2.5 mm wide, adaxially somewhat complanate especially in distal part; blade narrowly elliptic or narrowly oblanceolate-elliptic, (11–) 13–17.5 cm long, (2.5–) 3.2–3.8 cm wide, base attenuate, apex acute or nearly so (scarcely acuminate); longitudinal veins 5–9(–10) (of which 5 are more conspicuous, and middle 3 become converged shortly in advance of the outermost 2 at base); cross veinlets numerous, more or less parallel, closely spaced. Flowering stem (including inflorescence) nearly erect or arcuate, to 18 cm long, shorter than leaves; peduncle 5–10 cm long, 1.5–2 mm in diam.; sterile bracts on peduncle often 3 (excluding those congested at base), triangular-lanceolate, to 18 mm long, 4 mm wide, acute, membranous; rachis of inflorescence 3–8 cm long in flower, 3–10 cm long in fruit. Pedicels ascending, terete, 0.2–1.5(–3.8) mm long in flower, to 5 mm long in fruit, subtended at base by 2 bracts scarious and concave proximally; the lower bract antrorse at bud stage, often retrorse in flower, ovate-triangular, to 13 mm long, 4 mm wide at base, acute; the upper (bracteole) antrorse, narrowly lanceolate or subulate, to 6 mm long, 1–1.5 mm wide. Flowers 7–23 per rachis, horizontal or slightly ascending. Perigone fleshy, 6-cleft, widely opening, conic, limb 8–11 mm in diam., dark bluish or greyish leaden in colour (Griffith 5836, K!); proximal tubular (syntepalous) part conic, 2.4–3 mm long; segments orbicular, broadly ovate or ovate, 3.8–4.5 mm long and wide, imbricate proximally, entire or sometimes slightly minutely crenulate-erose along distal margins, rounded or obtuse at apex, unicostate. Stamens 6; filaments connate, forming fleshy corona orbicular at base, 4.5–5.5 mm in diam., flat proximally, distally raised at periphery of central orifice, slightly notched between anthers, orifice 2.2–2.5 mm in diam.; anthers sessile, dorsally attached to distal inner portion of corona, ovate, retuse at both ends, 0.8–1 mm long, 0.9 mm wide, bilocular, introrse, recurved when dehisced and dry. Pistil 1, tricarpellate, half-inferior, distal free part broadly subconic (subpyramidal), 1.3–1.6 mm long; ovary (free part) convex, 0.3–0.5 mm high, trilobed, triloculate; ovules 3–4 per locule, borne at base of central axis of ovary, narrowly ellipsoid; style pyramidal, 0.8–1.4 mm long including stigma, with 3 intercarpellary septal wings; stigma triparted, 0.8–1 mm wide, lobes oblong-ovate, 0.4–0.5 mm long, slightly descending distally. Seeds piriform-ovoid, 6–8 mm long, 5–6.5 mm wide.

Additional specimens examined (paratypes):― INDIA. East Bengale: Mishmee, W. Griffith 5836 (K-000099368–lectoparatype of P. violacea var. minor ; L-1449940*–isolectoparatype of P. violacea var. minor ; NY-00319821*–isolectoparatype of P. violacea var. minor ; P-00753590!–isolectoparatype of P. violacea var. minor ).

Distribution:―NE India (Khasia, Mishmi).

Habitat:―This species occurs at elevations up to 1220 m in Khasia.

Phenology:―Flowering and fruiting in November and December.

Etymology:―The specific epithet refers to a locality of this species.

Taxonomic relationships:― Peliosanthes khasiana is closely allied to P. violacea , but differs by the smaller leaf blades (11–17.5 × 2.5–3.8 vs. 18–49 × 4–11 cm) with fewer longitudinal veins (5–10 vs. 18–43), shorter pedicels (0.5–1.5(–3.8) vs. 2–8 mm long in flower), dark bluish or greyish leaden (vs. white or pale yellowish) perigones, slightly larger anthers (0.8–1 vs. 0.5–0.7 mm long), style with 3 narrow intercarpellary (septal) wings (vs. without wings), and slightly larger stigmas (0.8–1 vs. 0.4–0.7 mm wide). It is also close to P. subspicata , but distinguishable by its smaller leaf blades (vs. 23–31 × 4.5–7.3 cm) with fewer veins (vs. 17–25), and slightly ascending or horizontal (vs. cernuous) flowers with dark leaden (vs. pale yellowish green or green) perigones. The distinctiveness of Peliosanthes khasiana has long been overlooked. It was previously referred by Baker (1879: 504) to P. violacea var. violacea or P. violacea var. minor , but it is apparently a distinct species with several unique features.As compared with closely allied P. violacea and P. subspicata , P. khasiana has smaller leaf blades with fewer longitudinal veins, as noted above. Of the five main veins of the leaf blades of P. khasiana , the middle three become converged shortly earlier than (or shortly in advance of) the two outermost ones at the base ( Figs. 2B, 2C ). In contrast, all of the main longitudinal veins of the other two congeners become converged together (simultaneously) at the base. This is another point distinguishing P. khasiana from the two related species.

Figures

FIGURE 1. Holotype of Peliosanthes khasiana from NE India: J.D. Hooker & T. Thomson s.n. (K-000099355, p.p, excluding the left larger leaf indicated by arrow).

FIGURE 2. Peliosanthes khasiana (J.D. Hooker & T. Thomson s.n., K-000099355) A. Inflorescence. B–C. Venation at base of leaf (arrowed); B. Adaxial view. C. Abaxial view.

FIGURE 3. Peliosanthes khasiana. A. Flower with two front perigone segments removed. B. Inner perigone segment, ventral view. C–E. Distal free part of pistil; C, D. Side views from two different angles. Intercarpellary septal wings arrowed. E. View from above. F. Dihisced anther on staminal corona, ventral view. G. Diagram of longitudinal aspect of flower. Scale at A for A–B; at C for C–F. Drawn by Noriyuki Tanaka from: J.D. Hooker & T. Thomson s.n. (K-000099355).