Ischaemum amboliense S.A.Bokil, Datar & R.K.Choudhary, 2021

Bokil, Sarang A., Choudhary, Ritesh Kumar, Tamhankar, Shubhada & Datar, Mandar N., 2021, A novel species of Ischaemum (Poaceae, Andropogoneae) from the northern Western Ghats, India, based on morphological and molecular data, Phytotaxa 501 (1), pp. 171-180 : 174

Ischaemum amboliense S.A.Bokil, Datar & R.K.Choudhary , sp. nov. ( Fig. 2 )

Type: — INDIA. Maharashtra: Sindhudurg, Satuli , at the base of Amboli Ghat , 15.91719° N, 73.89581° E, 85 m. asl., 22 October 2019, M. N . Datar & S. A . Bokil 1605 (holotype: AHMA, isotypes: AHMA, BSI) .

Annuals. Culms tufted with stilt roots, erect, 150–180 cm tall, nodes hairy. Leaf-sheath laterally compressed, keeled on back, shorter than internodal region, 7–9 × ca. 0.6 cm; ligule sub-coriaceous, ovate, 0.4–0.5 cm long, hairy. Leaf blade lanceolate, 10–15 × 0.5–0.7 cm, rounded at the base without the petiole, apex acute, sparsely hairy on both sides. Racemes 2, paired, appressed, 7–9 cm long, well-exerted on long peduncle 7–8 cm from the leaf sheath, glabrous. Joints of rachis linear turbinate, 0.4–0.5 cm long, crustaceous, glabrous. Callus crustaceous, glabrous. Sessile spikelets: glabrous. Lower glume of sessile spikelets asymmetrically oblong 0.5–0.6 × ca. 0. 2 cm, with 3 – 4 distinct side nodules, margins entirely and evenly inflexed from base to apex with distinctly winged on one side and obscurely winged on another side, crustaceous in lower one-third region and herbaceous towards apical two-third regions. Upper glume of sessile spikelet boat-shaped, 0.4–0.5 × ca. 0.2 cm, apex bicuspidate, with a membranous wing on one side. Lower staminate florets: lower lemma lanceolate, 0.3–0.4 × ca. 0.1 cm, hyaline, distinctly winged on both sides towards apex, apex acute, hyaline; lower palea lanceolate, 0.3–0.4 × ca. 0.1 cm, hyaline, apex acute; stamens 3, ca. 0.2 cm long. Upper sterile florets: upper lemma oblong-lanceolate, 0.3–0.4 × ca. 0.1 cm, cleft at basal region, awned, hyaline, lobes acute at apex; awn geniculate, 1.5–2 cm long; upper palea oblong-lanceolate, 0.3–0.4 × ca. 0.1 cm, obtuse at apex, hyaline. Stamens and carpel absent. Pedicelled spikelets: asymmetrically oblong-lanceolate, 0.5–0.6 × ca. 0.1 cm, unawned, glabrous. Pedicel 0.1–0.2 cm long, crustaceous, glabrous, less than one third the length of sessile spikelet. Lower glume deltoid, asymmetrically oblong-lanceolate, 0.4–0.5 × 0.1–0.2 cm, coriaceous; margins narrowly and evenly inflexed from base to apex, broadly winged on one margin, lodicules 2, cuneate, 600–700 µm long. Upper glume boat-shaped, 0.4–0.5 × ca. 0.1 cm; apex acute. Lower staminate floret: lower lemma 0.4–0.5 × 0.1 cm, lanceolate, apex acute, hyaline; lower palea elliptic-lanceolate, 0.4–0.5 × 0.1 cm, apex sub-acute, sub-hyaline; stamens 3. Upper hermaphrodite florets: upper lemma ovate-oblong, 0.3–0.4 × ca. 0.1 cm; apex subacute, hyaline; upper palea ellipticlanceolate, 0.3–0.4 × ca. 0.1 cm, hyaline; stamens 3; ovary oblong-lanceolate; style, 0.1–0.2 cm long; stigma ca. 0.2 cm long, lodicules 2, 300–400 µm long. Caryopsis not seen.

Phenology:— Ischaemum amboliense is a therophyte with stilt roots. Flowering is seen during October–December. Pollination occurs through anemophily. The plant starts drying in late December when the water surrounding it recedes. In the areas which retain water till the start of summer, flowering can be seen up to March. Though we have not observed caryopsis on the spikelet, the newly sprouted seedlings were observed in the surrounding region. In addition to its prominent vegetative reproduction by sprouting shoots on old tillers, the plant also seems to be propagated through caryopsis.

Habitat:— Ischaemum amboliense grows in marshy places along the muddy banks of annual streams, where it grows in association with Isachne sp. and Cyperus sp. It is also found in the abandoned rice fields where monsoon water gets accumulated and stays till winter.

Figures

FIGURE 2. Ischaemum amboliense. a: habit, b: raceme, c–k: sessile spikelets, c: dorsal view of lower glume showing wing, d: ventral view of lower glume showing side nodules, e & f: upper glume, g: lower lemma, h: upper lemma, i: lower palea, j: upper palea, k: stamens of lower florets, l–v: pedicelled spikelets, l: lower glume, m: upper glume, n: lower lemma, o: upper lemma, p: lower palea, q: upper palea, r: stamens of lower florets, s: stamens of upper florets, t: carpel of upper florets, u: upper floret lodicules, v: lower floret lodicules. w: joint. (Scale: b: 2 cm, c–w: 1 mm)