Stuckenia pectinata (L.) Börner

J. R. Timberlake, E. S. Martins (2009). Flora Zambesiaca, Vol 12 (part 2). Royal Botanic Gardens, Kew

Type

Type Austria, Burser s.n. (UPS, Burser Herb. X124, lectotype chosen by Haynes in Taxon 35 569, 1986).

Morphology General Habit

Rooted submerged aquatic with adventitious roots at rhizome nodes; rhizome perennial, slender to very robust, terete, sometimes developing starch-filled tubers (generally absent in tropical plants) surrounded by a scaly leaf at end of the growing season

Morphology Stem

Stems annual to perennial, to 4 m long and 0.5–2 mm in diameter, filiform to relatively robust, terete, sometimes pink, usually much-branched

Morphology Leaves Stipules

Stipules persistent, 10–70 mm long, forming a convolute sheath, fused with leaf base for 8–65 mm and ending in a free ligule 3–15 mm long, rounded, obtuse or truncate, later disintegrating into fibres

Morphology General Scales

Intravaginal scales 0.4–0.6 mm long

Morphology Leaves

Floating leaf always absent Submerged leaf sessile, (20)30–125(300) 0.2–4 mm, 24–160(200) times as long as wide, filiform to linear, sometimes robust, bright to olive green, straight and grooved at base, entire at margins, the narrower leaf acute to finely acuminate at apex, sometimes the broader leaf rounded or obtuse and mucronate; midrib bordered on each side by one to several air channels, lateral veins 1–2 on each side, inconspicuous

Morphology Reproductive morphology Inflorescences Peduncles

Peduncles 20–100(450) mm long, 1.5–5(10) times as long as 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, 13–35(60) mm long in fruit

Morphology Reproductive morphology Flowers Tepal

Tepals orbicular to elliptical, 1–3 mm long

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers 0.8–1.3 mm long

Morphology Reproductive morphology Flowers Gynoecium Carpels

Carpels 4; stigma borne on a short but distinct style

Morphology Reproductive morphology Fruits

Fruitlets 3.3–4.7(5.1) 2–3.6 mm, asymmetrically obovoid, ventrally nearly straight, dorsally very convex, hardly 3-keeled; beak 0.2–0.6 mm long, ventral, rarely subventral-Stem anatomy stele of four bundles, mostly oblong; endodermis of U-type; interlacunar bundles present (in ± complete ring), subepidermal bundles few or absent; pseudohypodermis present, 1(2)-layered.

Distribution

Cosmopolitan, widely distributed across Africa from North Africa, Mauritania, tropical NE and E Africa, to Congo, Angola, Namibia, South Africa, Caprivi, Zambia, Malawi, Mozambique. Madagascar and the Mascarenes.

Ecology

Lakes, rivers, irrigation canals, 50–300 cm deep, also in brackish and polluted water; often forming extensive dominant patches and becoming a serious water weed, blocking water flow in irrigation and drainage canals; sea level–1800 m, up to 2850 m in Ethiopia.

Conservation

Conservation notes Widely distributed; not threatened. An important food source for many waterfowl species.

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/168962/120220519

Conservation

LC - least concern

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