Chlorophytum sikkimense P.Rai, 2022

Rai, Pramod, 2022, Chlorophytum sikkimense (Agavoideae; Asparagaceae): a new species from Sikkim Himalaya, Phytotaxa 567 (2), pp. 200-204 : 201

Chlorophytum sikkimense P.Rai , sp. nov. ( Fig. 1 )

Type:— INDIA. Sikkim, Namchi, Sirisay forest, 656 m a.s.l, N 27°10’33.03’’, E 88°20’16.28’’, collected in nature on 3 June 2020 Pramod Rai ; the herbarium specimen prepared from the living cultivated plant on 10 June 2021, Pramod Rai PO147 (holotype BSHC: acc. No 0302; isotype LBH) .

Diagnosis:—Most similar to C. assamicum but differs in rhizome reduced to disc (vs. horizontal), aristate and hairy fertile bract apex, angled pedicel jointed above middle, longitudinally dehiscing anther and white ovary.

A perennial herb, 15–30 cm tall growing solitarily or in clumps. Rhizome reduced to a disc, 1–1.5 cm across, bearing numerous (100–120) white fusiform fleshy roots ending with fibrous roots, 10–30 × 0.3–0.6 cm. Cataphylls 1–2 without remnant of leaves external to them. Foliage leaves 7–11, rosulate, linear, sessile, 10–56 × 3–5 cm, green, shiny above, pale greenish beneath with prominently 28–34 veins, apex usually acute in outermost leaves and acuminate in inner leaves, margin entire to undulate, sub-hyaline, canaliculate. Scape solitary, bracteate, 7–28 cm, including inflorescence, unbranched or occasionally branched up to 3 at the lowermost node of inflorescence, raceme to 1/3 rd of the scape length. Inflorescence with 3–10 nodes per axis with 4–5 flowers at each node. Scape bract 1 or occasionally absent, linear, 6.5–7 × 0.3–0.4 cm, apex acuminate with mucro ca. 2 mm long. Inflorescence sterile bract lanceolate, more rigid as compared to scape bract, 2.5–3 × 0.3–0.4 cm, apex acuminate with mucro 1–1.5 mm long. Bract subtending floral node linear caducous, white basally and green apically, c. 7-nerved, 1–2.5 × 0.3–0.4 cm. Floral bract triangular, caducous, 2–4, c. 4 mm long and 3–4 mm across, veins obscure. Pedicel 0.8–1.5 cm long, roughly quadrangular or trigonous, slightly twisted white and turning green when fruit is matured, jointed above middle, sometimes just beneath the base of perigone segments. Flowers white, faintly fragrant, pedicellate, 2 cm across. Perigone segments 6, perpendicular to pedicel or reflexed on next day, 3 at inner and outer whorl each. Outer segments linear 1.2–1.4 × 0.2–0.3 cm, white, slightly greenish dorsally at apex, apex acute, veins inconspicuous; inner segments similar to outer ones, slightly smaller, apex acute. Stamens 6, introse, erect, 0.8–1.3 cm long, filament slightly longer than anther; filaments 5–7 mm long, white, tapering towards apex, smooth; anther yellow, basifixed, 4–6 mm long, dehiscing through longitudinal slits. Ovary sessile, white, globose or hemispherical, 1.5 mm across, trigonous, glabrous; style slender, glabrous, 1.5 cm long, exceeding stamens and declinate. Capsule green at maturity, trigonous, c. 1 cm across, 3-sulcate, with 2–6 seeds in each locule. Seeds black, shiny, discoid, minor depression at middle, 3–4 mm across; testa papillose, papillae blunt, minute and aggregated at middle.

Phenology:—Flowering from May to July. Fruiting from June to November.

Distribution and habitat:— Chlorophytum sikkimense is currently known only from the type locality. Plant was predominantly growing under bamboo ( Dendrocalamus hamiltonii ) thickets on a well-drained loam of tropical mixed deciduous forest at an elevation of 656 m. Population of 53 individuals consisted of randomly scattered individuals over 2 km sq. km. Some individuals were growing in complete shade while other in partial shade and some in open areas. Higher plants were observed mostly in open or less shaded areas. Growing in home garden with relatively less shade resulted in bigger plants with branched scapes. The species was associated with Amorphophallus napalensis (Wall.) Bogner & Mayo. , Boesenbergia hamiltonii Mood, S.Dey & L.M. Prince , Disporum cantoniense (Lour.) Merr. , Liparis plantaginea Lindl. , Malaxis khasyana (Hook. f.) Kuntze. , M. ophrydis (Konig) Ormerod. , etc. The leafy shoot remains for about 6 months (late April to October) then dries up leaving rhizome and seeds are shed.

Etymology:—Species epithet is named after the Northeastern state of India – Sikkim.

Proposed IUCN conservation status:—The new species was found only in a single locality with ca. 150 individuals. Therefore, a tentative criteria for it is Endangered D (EN) according to IUCN Criteria (IUCN 2022).

Taxonomic relationships:— Chlorophytum sikkimense is closer to C. assamicum D.Borah & A.P. Das in Borah et al. (2019: 123) and C. breviscapum because of plant and flower sizes, habit, habitat, unbranched scape shorter than leaves and reproductive period. It is also related to C. assamicum due to the lack of tubers, presence of both scape and inflorescence sterile bracts and smooth filaments but differs in rhizome reduced to disc (vs. horizontal), aristate and hairy fertile bract apex (vs. acuminate and glabrous), angled pedicel jointed above middle (vs. cylindrical and jointless), longitudinally dehiscing anther (vs. dehiscing through apical pore) and white ovary (vs. greenish). It shares additional similarity also with C. breviscapum with their rhizome that is reduced to disc, pedicel jointed above middle, anther dehiscing longitudinally and white ovary but differs due to absence of leaf remnants at plant base (vs. present), lack of tuber (vs. present), scape bract and inflorescence sterile bract present (vs. absence), pedicel angular (vs. cylindrical) and smooth filaments (vs. papillose). Differences amongst them are provided in Table 1 .

Figures

FIGURE 1. Chlorophytum sikkimense P.Rai. A. Habit. B. A capsule. C–D. Infrutescence. E. apical part of scape showing branched raceme. F. A scape showing sterile bracts (inflorescence and scape). G. Bracteole. H. Bract. I. Leaf, abaxial side. J. Leaf, adaxial side. K. Stamens. L. Basal part of pistil. M. A pedicel showing articulation. N. Seed. O. Transverse section through ovule. P. Inflorescence sterile bract apex. Q. Scape bract apex. R. Inflorescence sterile bracts from same scape (left - upper, right - lower).