Aponogeton crispus Thunberg (1784: 73)

Manawaduge, Chapa G. & Yakandawala, Deepthi, 2018, Morphometrics and taxonomic update to the Sri Lankan Aponogetonaceae, Phytotaxa 365 (3), pp. 201-224 : 214

3. Aponogeton crispus Thunberg (1784: 73) (as ‘ A. crispum ’)

Spathium crispum (Thunb.) Voigt (1845: 694) . Type:— Thunberg s.n. (UPS).

Aponogeton echinatus Roxburgh (1832: 210–211) . Spathium echinatum (Roxb.) Voigt (1845: 694) . Type:— Bourne 3200 (neotype K!, designated by Bruggen (1970), isoneotypes K, CAL).

Tuber globule or obovoid, up to 2.8 cm Ø. Submerged leaves very variable in shape and dimensions, up to 26 × 9 cm, linear or narrowly lanceolate, apex retuse and base cordate, margin undulate, Protrude midrib with 6–8 parallel veins. Petioles up to 38 cm long, brittle, bluntly triangular. Floating leaves very variable in size, up to 18 × 4 cm, lanceolate or (narrowly) ovate; apex cuneate with a blunt tip and base slightly cordate, margin flat, Protrude midrib with 6–8 parallel veins. Petioles up to 71 cm long. Peduncle up to 80 cm, widening towards the inflorescence. Spathe up to 2.5 cm, caducous. Inflorescence with 1 spike of up to 18 cm, whitish pink, fragrant, densely or rather laxly flowered, florets turned towards all directions. Tepals 2, rounded,1.3–2.1 × 1.1–2.0 mm, whitish pink, persistent, 1-nerved. Stamens 6, 1.0– 2.2 mm, filaments slightly widening towards the base, whitish pink, anthers bluish green. Ovaries 3, whitish pink, 1.0–1.7 × 0.5–1.3 mm, often with some small excrescences, ovules 2. Infructescence up to 20 cm, slightly dense or laxly. Folicals up to 10 × 6 mm, elongated, triangular, with rough coat and a short, terminal, curved beak. Seeds with a simple testa, relatively thick and transparent. Embryo up to 7.5–8.8 × 3.3–4.0 mm, plumule attached near the base of the embryo and in a very wide groove.

Phenology:— Flowering throughout the year with flowering intensity increasing just after the rainy season.

Distribution:— India and Sri Lanka (intermediate and lowland dry zone).

Ecology:— Grows luxuriously in large lakes, ponds and tanks in the lowland dry zone.

Uses:— Tubers and inflorescence are eaten.

Notes:— According to Bruggen (1987) A. crispus is very variable in habit and he speculates that there may exist varieties. This could refer to Aponogeton dassanayakei , which was identified erroneously as A. crispus in literature ( Bruggen 1987) supporting the occurrence of A. crispus in Colombo (Western Province), but during our study we never encountered A. crispus but A. dassanayakei in the region. Aponogeton dassanayakei superficially resembles A. crispus but can be verified with the tuber characters in case of a doubt.

Specimens examined:— SRI LANKA. Anuradhapura District : Tirappane, 13 Jun. 2015, Manawaduge & Yakandawala 118 ( PDA!) ; Kebithigollewa , 13 Jun. 2015, Manawaduge & Yakandawala 119 ( PDA!) ; Tittagone Wewa , 13 Jun. 2015, Manawaduge & Yakandawala 120 ( PDA!) ; Jaffna District : Mile 171, Jaffna Road, 8 Jul. 1971, Meijer 774 ( L, PDA!, US) ; Kandy District : RBG (Peradeniya), 26 Sep. 2014, Manawaduge & Yakandawala 111 ( PDA!) ; Kurunegala District : Ibbagamuwa, 26 Jun. 1967, Amaratunga 1348 ( PDA!) ; Matale District : Naula, 25 May 2014, Manawaduge & Yakandawala 101 ( PDA1 ) ; Pidurangala , 25 May 2014, Manawaduge & Yakandawala 102 ( PDA!) ; Pidurangala , 25 May 2014, Manawaduge & Yakandawala 103 ( PDA!) .