Ischaemum mistryi S. N. Landge & Shinde, 2021

Landge, Shahid Nawaz & Shinde, Rajendra D., 2021, Ischaemum mistryi (Poaceae: Andropogoneae): A new remarkable species from Sub-Tropical Evergreen Forest, India, Phytotaxa 509 (3), pp. 272-280 : 273-278

Ischaemum mistryi S. N. Landge & Shinde , sp. nov. ( Figs. 1 , 2 & 3 )

Type:— INDIA. Maharashtra state: Kolhapur district, Tilari Ghat , 724 m above mean sea level (approx.), 15°48’42.0”N 74°12’43.5”E, 10 October 2019, Shahid Nawaz TG-01 (holotype BLAT, Isotypes BLAT) .

Diagnosis:— This species is similar to Ischaemum mangaluricum in shape of the bi-partite upper lemma (deeply clefted, almost 2/3 of its length) in the sessile spikelet but differs from which in combination of certain characters, such as, the lower glume of the sessile spikelet without a transverse ridge below the apex (vs. with a characteristic transverse ridge below the apex), lower glume linear, oblong-lanceolate, tapering upwards (vs. oblong not tapering upwards), keel of lower glume not noduled, if at all noduled then obscure only 2–4 on one keel (vs. almost always with distinct 4–5 nodules on both the keels), lower glume without an auriculate wing (vs. with a distinct auriculate wing at apex), basal sheath villous (vs. glabrous), lower glume of pedicelled spikelet 13–22 nerved (vs. 11–13 nerved).

Description:— Perennial, 30–90 cm high, densely tufted, non-stoloniferous, ascending, sparsely branched, long slender herb. Basal portion studded with multiple stump-like, dense, nodular projections (remnants of old culms or emerging stem) forming a prominent tussock-like thicket. Cataphylls are few, 5.0–7.0 mm long, ovate-lanceolate, keeled in the middle, acute, membranous (but not pungent or tough), glabrous, multi-nerved. Culms slender, 3–4 nodded, compressed at the base till the first node and thereafter angled or sub-terete, tough, glabrous; nodes tinged with purple or maroon, sparsely bearded (hairs caducous). Basal sheath, ribbed, strongly laterally compressed, keeled or obtuse, reddish to purplish, striated, prominently villous with short white hairs; usually 3.0–5.0 cm long (but also ca. 12.5 cm long); upper sheath 15–20 cm long. Ligule 5.0– 10 mm long, hyaline membranous (becoming scarious and bipartite later), acute to obtuse at the apex, joined by a lateral, continuous extension of a sheath which is dotted with trichomes. Leaves long, pubescent, drooping, mostly congregated near the base (macrescent) only few cauline; blades 8.5–50× 0.6–1.2 cm, linear-elliptic, tapered at both the ends, multi-nerved (usually 8 nerved), keeled on the ventral surface, glaucous on the abaxial surface whereas dark green above, densely setaceous with bulbous-based trichomes throughout (trichomes are caducous leaving only bulbous bases in older leaves); median keel continues further downward as a canaliculated, stiff pseudo-petiole without lamina, 3.0– 20 cm long, densely setaceous. Inflorescence high exserted on the long peduncle consists of bi-conjugate spiciform raceme 6.0– 11.5 cm long. Spikelets in a heteromorphic pair: sessile awned hermaphrodite and counterpart pedicelled, staminate or hermaphrodite but always unawned. Sessile spikelet (6.0–) 7.0–8.0 (–10) mm long (including the callus, ca. 1.2 mm long), only the lowest pair homogamous or not, lower floret staminate and upper hermaphrodite: lower glume 6.0–8.0×1.8–2.0 mm, linear, oblong-lanceolate, tapering upwards and slightly curling, mostly glabrous (hairy below the middle in the upper portion of raceme), coriaceous, somewhat crustaceous, herbaceous near the apex only, 2 keeled, margin evenly inflexed throughout, rounded in lower portion and sharply bent upwards, winged in upper 1.5/4 on the margin towards the rhachis internode (wing serrulated and glabrous, ca. 1.2 mm broad), also slightly winged on another margin, nerves 12–19 distinctly anastomosing, evanescent below the middle, completely smooth or with 2–4 obscure nodules on one keel facing the rhachis, never joined by ridges on the back, apex hyaline, acute to bi-dentate, membranous, sub-apical transverse ridge is absent; upper glume 6.5–8.0× ca. 3.0 mm (broadest at the base), ovate, cymbiform, scabrous, pubescent, subcoriaceous, tough, obscurely 3–5 nerved, apex acuminate or finely aristate; lower lemma 7.0× 1.7 mm, elliptic, acute, glabrous, hyaline membranous, 3 nerved (2 lateral nerves sub-marginal), margin inflexed throughout, eciliate, broader towards the tip; lower palea ca. 6.0× 1.3 mm (broadest in the middle), oblong-elliptic, characteristically tougher than its lemma (in lower portion of the raceme), glabrous, 2 keeled, margin sharply inflexed, hyaline, membranous, fragile, eciliate, smooth, broader below the acute apex; upper lemma ca. 5.2 mm long, hyaline membranous, bi-partite almost 4/5 of its length with glabrous, acuminate lobes; geniculate awn (column 8.0 mm and bristle 10 mm long) issuing from the sinus; upper palea ca. 5.1×1.0 mm (unopened), oblong-elliptic or obspatulate, hyaline-membranous, glabrous, 2 keeled, margin sharply inflexed, in lower 2/3, broadest above the base, apex sub-acute to obtuse. Stamens 3, anthers ca. 3.2 mm long; pistil with ovary ca. 1.0 mm and style very long with terminal plumose stigma; lodicules 2, ca. 0.8–1.1× 0.5 mm, hyaline-membranous, obliquely-tridentate, glabrous. Pedicelled spikelet 6.0–7.0 mm long, broadly winged on one margin, lower floret staminate and upper hermaphrodite: lower glume 6.0–7.0×3.0– 3.3 mm (broadest below the middle), elliptic-lanceolate (glume without wing oblong-lanceolate), convex on the dorsal side, glabrous (becoming hairy below the middle upwards in raceme), coriaceous, crustaceous, tough, margin evenly inflexed (with hyaline, fragile membrane above the middle), rounded on the keel in lower portion (sharply inflexed towards the apex) and slightly broader, strictly glabrous, nerves green 13–22, evanescent below the middle, distinctly anastomosing above the middle, broadly winged on one margin length-wise, another margin slightly winged or not, apex hyaline membranous, no nodules or ridges on the keels or across the back; upper glume 7.0× 2.5 mm (equally broad in the middle), sub-equal to lower glume, oblong-elliptic, sub-coriaceous-membranous, acute, keeled, cymbiform, glabrous, scabrous on the back, pale-brownish, obscurely 5 nerved, anastomosing at least in the upper portion, margin hyalinemembranous, broader above the middle & becoming narrow below; lower lemma 6.2× 1.1 mm, elliptic-lanceolate, oblong, acute, flat, hyaline-membranous, glabrous, 3 nerved (lateral nerves fine and sub-marginal), flaps broad near the apex becoming narrow downwards; lower palea elliptic-oblong, sub-equal to its lemma, apex obtuse, glabrous, 2 keeled, somewhat tough membranous; stamens 3, anthers 2.0– 2.5 mm long; upper lemma ca. 5.5×2.0 mm (broadest in the middle), elliptic, acute or sub-aristate, cymbiform, hyaline-membranous, glabrous, 1 nerved, slightly tinged in pale-brown in the middle; upper palea ca. 4.5×1.0 mm (broadest in the middle), narrow-elliptic, acute, glabrous, hyaline-membranous, flaps narrow, 2 nerved; stamens 3, anthers 3.1 mm long; ovary 0.7 mm long, style, flat, long, stigma plumose, dense.

Etymology: — The epithet honors Dr. Manek K. Mistry (Retired professor in Botany Department, St. Xavier’s College (Autonomous) Mumbai) for his invaluable and largely unrecognized contributions in the flora of Ratnagiri District, Maharashtra.

Distribution: — Tilari Ghats, Kolhapur district, Maharashtra, India. A very rare, apparently endemic species.

Habitat and Ecology: — Mostly inhabit in open, wet, high altitude grasslands: near rivulets; on the periphery of ephemeral pools during the monsoon; through the stony crevices on the exposed rocky outcrop on the flanks of the wide streams; least in the shade but only near water bodies in the dense forest.

Flowering and fruiting: — Flowering is seen during the October and fruiting at the end of the November.

Associated species: — In the open wet monsoonal grasslands, it is often associated with Chrysopogon castaneus Veldkamp and Salunkhe (2000: 59) , Dichanthium paranjpyeanum ( Bhide 1912: 514) Clayton (1978: 579) , Rotala sp. , Eriocaulon sp. , Paspalum canarae (Steudel 1853: 58) Veldkamp (1973: 72) , Dimeria blatterii Bor (1949: 70) and rarely with Ischaemum impressum Hackel (1889: 210) but then in the dense forest.

IUCN Conservation: — The grass is known only from the two localities in Tilari Ghat, Maharashtra, with few individuals growing.Since the area wherein these populations exist is quite vulnerable for the proposed dam construction plan. All the individuals, if counted are less than 40 and occur within the magnitude of 2 km 2. These observations are based on 14 days of extensive field study in Tilari Ghat and we found that this grass is apparently very rare. Thus, based on the IUCN Red List Categories and Criteria (2019), we assess this species under B2ab (ii,v); C2a (i)+D as Critically Endangered (CR). Further population and conservation study is necessary if the dam construction plan is sanctioned. There is a fair possibility that population of this grass may experience a threat of extinction in future.

Taxonomic Note: — The parts such as rhachis internode, pedicel, spikelets and other floral organs differ in quantitative and qualitative scale in a single raceme from base to apex. Pedicel in the lower portion of raceme is shorter than 1/3 of the sessile spikelet but in the upper most spikelet becomes longer than 1/3. Rhachis internode becoming more linear, dentate at the apex, elongated and glabrous in upper portion of the raceme, so that the terminal one only partially ciliate in the lower half. Pedicelled and sessile spikelets those were initially longer and glabrous eventually becoming shorter and ciliate upwards. The wing of the sessile spikelet becomes diminished and less known. Lower palea of sessile spikelet which was tougher in the lower portion of the raceme eventually becomes hyaline and fragile in the upper portion. This grass has characteristically larger lodicules that measure up to 1.1 mm long.

(Photography by: Shahid Nawaz)

(Photography by: Shahid Nawaz)

In ( Fig. 3 ), lower glumes of sessile spikelets: C1 (wingless or very minutely winged), C2 (with a distinctly long wing) and C3 (uppermost spikelet in raceme) exhibit a range of variations in the shape and presence of wing. Further, E1 and E2 represent shapes of the rhachis internode from the base and apex of the raceme respectively. Later, H1 and H2 exhibit differences in the shape of the upper palea of sessile spikelet.

This is a very deep-rooted, tough, perennial grass forming a distinct thicket in the mud, quite raised in appearance — mostly consisting of the relics of the old culms with highly reduced internodes, whereby it proliferates. These thickets make it very difficult to deracinate without destroying the plant.

*Information is based on (Hackel 1889, Hooker 1896, Fischer 1933, Bor 1960 & 1962, Potdar et al. 2012) and also the herbarium specimens examined at BLAT.

Figures

FIGURE 1. Ischaemum mistryi. A. Habit. B. Emerging inflorescence. C. Basal raised thicket. D. Spiciform-raceme young and dried. E. Petiole. F. A short portion of a leaf blade.

FIGURE 2. Ischaemum mistryi. A. Close-up of basal portion. B. Villous basal sheath. C. Collar. D. Upper most leaf (acute). E. Drooping leaves. F. Laterally compressed basal sheath. G. Node.

FIGURE 3. Ischaemum mistryi (A and C–V) and Ischaemum mangaluricum (B). A. Spikelet (I. mistryi). B: B1. Spikelet. B2. Rhachis internode (I. mangaluricum). C–M: Sessile spikelet and rhachis. C. Lower glume (dorsal). D. Lower glume (ventral).E. Rhachis internode. F1. Lower lemma (dorsal). F2. Lower lemma (ventral). G1. Lower palea (dorsal). G2. Lower palea (ventral). H. Upper palea. I. Upper lemma. J2. Upper glume (ventral). J2. Upper glume (side view). K. Anthers of upper floret. L. Pistil. M. Lodicules of upper floret. N–U: Pedicelled spikelet. N1. Lower glume (dorsal). N2. Lower glume (ventral). O1. Upper glume (ventral). O2. Upper glume (side view). P1. Lower lemma. P2. Lower palea. Q. Upper lemma. R. Upper palea. S. Anthers of upper floret. T. Lodicules of upper floret. U. Pistil. V. Basal portion of the plant. (Illustrated by: Shahid Nawaz).