Stuckenia pectinata (L.) Börner

Distribution

Biogeografic region: Andean. Native to Colombia. Colombian departments: Nariño.

Habit

Herb, Aquatic.

Conservation

IUCN Red List Assessment (2021): LC.

Potamogetonaceae, J.J. Symoens. Flora of Tropical East Africa. 2006

Morphology General Habit

Rooted submerged aquatic with adventitious roots at the nodes of the horizontal shoots.

Vegetative Multiplication Rhizomes

Rhizomes perennial, slender to very robust, terete, whitish, sometimes developing tubers filled with starch and surrounded by a scaly leaf at the end of the growing season (such tubers generally absent in tropical plants).

Morphology Leaves

Submerged leaves bright green to olive green, sessile, (20– )30– 125(– 300) mm long, 0.2– 4 mm wide, 24– 200 times as long as wide, linear, canaliculate or flattened, straight at base, entire at margins, the narrower leaves acute to finely acuminate at apex, sometimes the broader leaves obtuse and mucronate; midrib bordered on each side by one to several air channels, lateral veins 1– 2 on each side, inconspicuous; stipules persistent, fused with the leaves for 8– 70 mm, forming a convolute and winged leaf base, ending in a free hyaline ligule, (3– )5– 15 mm long, obtuse, rounded or truncate, later disintegrating into fibres; intravaginal scales 0.4– 0.6 mm long; floating leaves always absent.

Morphology Reproductive morphology Inflorescences

Peduncles 20– 100(– 450) mm long, 1.5– 5(– 10) times as long as the fruiting spike, as thick as the stem, flexuous; spikes (4– )8– 14-flowered, with 2– 7 pairs or whorls of flowers, contiguous at first, later distant, or the upper groups ± contiguous, 13– 35(– 60) mm long when in fruit.

Morphology Reproductive morphology Flowers

Tepals orbicular to elliptical, 1– 3 mm long; anthers 0.8– 1.3 mm long; carpels 4; stigmas borne on a short but distinct style.

Morphology Reproductive morphology Fruits

Fruitlets brown,(2.5– )3.3– 4.7(– 5.1) mm long, 2– 3.6 mm broad, asymmetrically obovoid, ventrally nearly straight, dorsally very convex, hardly 3-keeled; beak 0.2– 0.6 mm long, ventral, rarely subventral.

Morphology Stem

Stem anatomy:stele of four bundles, mostly oblong; endodermis of U-type; interlacunar bundles present (in 1 ± complete ring); subepidermal bundles few or absent; pseudohypodermis present, 1-(– 2)-layered. Stems annual to perennial, up to 4 m long and 0.5– 2 mm in diameter, filiform to relatively robust, terete, sometimes pink, usually richly branched.

Figures

Fig. 2 (p. 6).

Habitat

Lakes, rivers, irrigation canals, also in brackish and in polluted water; water depth up to 3 m; forming often extensive monospecific patches; also a serious water weed, often blocking the waterflow in irrigation and drainage canals; 350– 2300 m

Distribution

subcosmopolitan, widely distributed in Africa, including North Africa, Madagascar and the Mascarenes Islands K1 K2 K3 K4 T1 T2 T4 T5 T7 U2