Ischaemum agharkarii M.N.Datar, R.K.Choudhary, P.D.Gorade, 2016

Gorade, Puroshottam, Datar, Mandar N., Choudhary, Ritesh Kumar & Pathare, Prajakta S., 2016, Ischaemum agharkarii (Andropogoneae, Poaceae), a new species from Northern Western Ghats, India, Phytotaxa 272 (1), pp. 89-93 : 90-93

Ischaemum agharkarii M.N.Datar, R.K.Choudhary, P.D.Gorade , sp. nov. ( Fig. 1 )

Type:— INDIA. Maharashtra: Pune District, Near Talegaon, Karanjvihire, 678 m, 18.8054°N, 73.7128°E, 16 October 2014, P. Gorade ARI–12 (holotype AHMA, isotypes CAL, BSI).

Diagnosis: —Hairy first node. Presence of side nodules on lower glume of both sessile and pedicelled spikelets. Band of hairs on ventral side of the lower glume.

Description: —Annuals. Culms tufted, terete, rooting at the lower nodes, 80–120 cm tall. Nodes glabrous except the first node towards raceme. Leaf sheaths 10–13 cm, glabrous or hairy; ligule membranous, 2–4 mm long, lower leaves tapering, upper rounded or cordate; leaf blades 10–20 × 0.7–1.2 cm, linear, glabrous or sparsely hairy, hairs present on only veins, base rounded or cordate, margin entire, apex acuminate. Racemes 2, appressed to each other hence appearing solitary, 6–8 cm long, hairy; joints 3–4 × 1.5–2 mm, hollow, clavate–turbinate, hairy on angles, transparent towards spikelet. Sessile spikelets 5–7 mm long, oblong–lanceolate, awned, purplish in color, callus bearded; lower glume pilose, 5–6 × 2–2.5 mm, ovate-oblong, margins inflexed, 9–11 nerved, 3–4 side nodules connected by shallow or deep ridges, chartaceous on upper side, apex minutely winged at one side and broadly at another (less than lower glume of pedicelled spikelet), margins of the wings serrulate, apex acute, hairy patch on ventral side of glume at 1/3 rd of the total length; upper glume 5–6 × 1.2–1.5 mm, pubescent, boat shaped, 4–5 nerved, 1–keeled, margins infolded, ciliate, dorsally keeled and minutely winged at apex, apex acute; lower floret male; upper floret hermaphrodite; lower lemma 5–5.5 × 1.2–1.5 mm, membranous, narrowly ovate, margins inflexed, ciliate, 3–nerved, translucent, apex acute; palea 5–5.3 × 1–1.3 mm, translucent, ovate, 2–nerved, apex acute; stamens 3, purplish–yellow, anthers 2.0– 2.5 mm long; lodicules 2, cuneate; upper lemma 4–4.5 × 1–1.2 mm, translucent, cleft at apex into 2 lobes, 5–nerved, awned from sinus; awn 18–20 mm long; palea 4–4.2 × 1–1.2 mm, hyaline, 2–nerved, margin ciliate, apex obtuse; lodicules 2; stamens 3, anthers 2–2.5 mm long; ovary oblong, styles 1.7–2 mm long, stigmas 1–1.5 mm long, plumose. Caryopsis 2.3–2.5 × 0.8–1 mm, oval, brown-purple. Pedicelled spikelets 5–6 × 2.3–2.5 mm, unawned, ovate, one side curved (towards winged side of lower glume) and other straight, hairy; pedicels of pedicelled spikelets 1–1.5 × 0.8–1 mm, clavate, conical (inversely), densely hairy on angles; lower glume 5–6 × 2.3–2.5 mm, pilose, ovate–obovate, broadly winged on one margin and other side minutely winged at apex, margins inflexed, hyaline at apex, 9–11 nerved, wing scabrid along margin, apex acute, minutely ridged with few nodules; upper glume 5–5.5 × 1.2–1.5 mm, pilose, boat shaped, ovate, 4–5-nerved, dorsally keeled, margins inflexed, hyaline at apex, apex acute; lower floret male; upper floret hermaphrodite; lower lemma 5–5.3 × 1.2–1.4 mm, hyaline, ovate, 2 nerved, margins ciliate, inflexed, apex acute; palea 4.8–5 × 1–1.2 mm, translucent, ovate, 2 nerved, margins infolded, sometimes wavy on one side, apex acute; stamens 3, anthers 2.5–3 mm long, yellowish in color with purple tinge; upper lemma 4.5–5 × 1.2–1.4 mm, oblongelliptic, margins infolded, hyaline, apex acute; palea 4–4.2 × 1–1.2 mm, broad towards base, narrow at apex, margins infolded, apex obtuse; stamens 3, yellowish in color with purple tinge, anthers 2.7–3 mm long; ovary oblong, style 1.2–1.5 mm, stigma 1–1.2 mm long; lodicules 2, cuneate. Caryopsis 2–2.2 × 0.8–1 mm, oval, purplish.

Etymology: —This species is named after Prof. S.P. Agharkar, founder Director of the Agharkar Research Institute and famous botanist for his contribution in the field of Indian Botany.

Taxonomic notes: — I. agharkarii shows remarkable similarities with two Indian endemic species i.e. I. travancorense and I. santapaui . However, it shows some striking morphological differences from them in having hairy first node, presence of side nodules on lower glume of both sessile and pedicelled spikelets and band of hairs on the ventral side of the lower glume. See Table 1 for other morphological comparisons.

Distribution & Habitat Ecology: —We found the new species growing in abandoned rice fields in moist, muddy areas and forming clumps at Karanjvihire village near Talegaon of Pune district in the northern Western Ghats of India ( Fig. 2). A state-wide survey of grasslands ( Datar 2016) revealed the distribution of this species only in the type locality. Therefore, this species is possibly endemic to the Eastern Slopes of Western Ghats characterized by moderate annual rainfall (1200–1500 mm) and mid elevation landscapes (700–900 m).

*Information based on Bor (1960), Clayton & Renvoize (1986) and Cooke (1908), and herbarium specimens studied.

Conservation Status: —According to the IUCN (2014) criteria we consider this new species as Data Deficient (DD). This species was collected from only one locality till date where it was growing in small populations of 40–50 individuals. More quantitative population data is needed for assessment of its true status.

Phenology: —Annual plant that sprouts after the advent of monsoon. Flowering starts in August. Peak flowering is seen in September-October. Grains are produced and dispersed after October.

Figures

FIGURE 1. Ischaemum agharkarii. A. Habit. B. First node. C. Collar. D. Joint. E. Sessile and pedicelled spikelet. (F–O. Sessile spikelet) F. Lower glume. G. Upper glume. H. Lower lemma. I. Lower palea. J. Stamens of lower floret. K. Upper lemma (awn partially removed). L. Upper palea. M. Stamens of upper floret. N. Pistil with lodicules. O. Caryopsis. (P–Y. Pedicelled spikelet) P. Spikelet with pedicel. Q. Lower glume. R. Upper glume. S. Lower lemma. T. Lower palea. U. Upper lemma. V. Upper palea. W. Stamens of upper floret. X. Pistil with lodicule. Y. Caryopsis. (All images from the holotype).