Aponogeton wolfgangianus S.R.Yadav, 2017

Yadav, Shrirang Ramchandra, 2017, A new species of Aponogeton (Aponogetonaceae) from India with critical notes on embryo morphology, Phytotaxa 328 (1), pp. 83-89 : 84

Aponogeton wolfgangianus S.R.Yadav , sp. nov. ( Figs. 1 , 2 )

Aponogeton wolfgangianus resembles A. jacobsenii but differs in the presence of both submerged and floating leaves (vs. mostly submerged leaves and extremely rare floating leaves), beaked fruits (vs. non-beaked fruits), obovate embryo (vs. elliptic embryo) and plumule attached at side of the embryo at the middle (vs. plumule attached at side of the embryo above the middle). Aponogeton wolfgangianus also resembles A. crispus in general morphology but differs in its obovate embryo (vs. elliptic embryo) and plumule attached at the side of the embryo at the middle (vs. plumule attached at the base of concave broadly grooved cotyledon).

Type: —INDIA. Kerala, Wayanad district, Panamaram, 11018.154’ N” 76015.084 ’ E ”, 698 meters, 23 Nov. 2015, S.R. Yadav 402 (Holotype CAL!, Isotypes BSI!, K!, SUK!).

Perennial fresh-water tuberiferous aquatic herb, tuber obovoid to cylindrical, 3–5 × 1–2 cm. Leaves numerous, dimorphic; submerged leaves thin, pale green, brittle, ovate to broadly elliptical, 20–30 × 5–6 cm, margin undulate, primary nerves 7–9; floating leaves elliptic rounded, 4–7 × 1–1.5 cm, base rounded, primary nerves 7–9, margin entire. Inflorescence many, pedunculate; peduncle 30–60 × 0.3–0.4 cm, slender, not thickened towards base of spike. Spathe up to 1.5–2 cm long, acuminate, caducous. Spike solitary, 8–16 cm long, laxly flowered, curved back, flowers turned all around. Tepals 2, glistening-white, c. 2 × 2 mm, broadly ovate. Stamens 6, 1.5–2.5 mm, filaments dilated towards base, anthers brown to violet, pollens yellow. Carpels 3, 1.7–2 × 1–1.5 mm, white, ovules 2 per carpel. Fruits 6–15 × 4–6 mm, smooth or echinate, beaked, beak curved, 5–10 mm long. Seeds 6–10 × 3–3.5 mm, with green or violet simple testa. Embryo obovate, 6–10 × 2.5–3.5 mm, non-appendaged, green; plumule at the side of the embryo at middle, cormatous part of embryo c. 2.5–5 × 2.5–4 mm, cotyledonary part concave-convex, 3–5 × 2–3 mm, green.

Phenology: —Flowering and fruiting from November to December.

Distribution and ecology: — Aponogeton wolfgangianus is so far known from Panamaram Village Lake, Wayanad district, Kerala, India. It occurs in fresh water ponds (at Panamaram village Wayanad) and only about 500 individuals have been located.

Habitat: — Aponogeton wolfgangianus grows at an altitude of 698 m, in freshwater pond. Major associates include Nymphaea rubra Roxb. ex Andrews (1805: 14) , Aponogeton undulatus , Oryza rufipogon Griffith (1851: 5–6) and Leersia hexandra Swartz (1788: 21) .

Eponymy: —The new species is named in honour of Wolfgang Theuerkauf, who established the Gurukula Botanical Sanctuary and contributed to conservation of plants of the Western Ghats.

Chromosome number: —2 n = 32.

Notes: —This species shows affinities with Aponogeton jacobsenii from Sri Lanka, but differs in its beaked fruits, obovate embryo and position of plumule. Morphological differences between A. wolfgangianus , A. jacobsenii de Wit (1983: 120) and A. crispus are listed in Table 1.

wolfgangianus .

Figures

FIGURE 1. Aponogeton wolfgangianus. A. Habitat. B. Habit. C. Inflorescence. D. Infructescence. E. Follicle. G, H, I. Embryo (Photos by S. R. Yadav). F. Embryo of Aponogeton jacobsenii (Photo provided by Deepthi Yakandawala).

FIGURE 2. Aponogeton wolfgangianus A. Habit. B. Inflorescence. C. Infructescence. D. Embryo. Illustrated by Shrikant Sutar.