Platostoma dilungense (Lisowski & Mielcarek) A.J.Paton

Lamiaceae (Labiatae), A.J. Paton, G. Bramley, O. Ryding, R.M. Polhill, Y.B. Harvey, M. Iwarsson, F. Willis, P.B. Phillipson, K. Balkwill, C.W. Lukhoba, D.F. Otieno, & R.M. Harley. Flora of Tropical East Africa. 2009

Type

Type: Congo-Kinshasa, Katanga, Kibara, Lisowski, Malaisse & Symoens 4814 (BR!, iso.)

Morphology General Habit

Aquatic perennial with slender creeping rhizomes, forming carpets in shallow water or small plants in mud

Morphology Stem

Stems slender, spongy, trailing, with ascending flowering shoots to 5–40 cm, simple or sparsely branched, with white patent to retrorse hairs

Morphology Leaves

Leaves opposite to ternate, sessile, submerged ones linearlanceolate, entire, 7–20 × 1–3 mm, glabrous (sometimes absent from dwarfed plants); aerial leaves lanceolate to elliptic or ovate, 3–15 × 1.5–8 mm, entire or with a few small teeth, acute to obtuse, base cuneate to rounded, subglabrous to appressed-pubescent on both surfaces and with sessile glands

Morphology Reproductive morphology Inflorescences

Inflorescences congested, 0.5–2 cm long with up to 8 ± contiguous verticils, subtended by 2–several leafy bracts and with a few smaller ones subtending verticils above, sometimes a few flowers in the axils below; bracts lanceolate to narrowly ovate, 5–10 mm long; pedicels filiform, 5–7(–12 in fruit) mm long, with spreading hairs

Morphology Reproductive morphology Flowers Calyx

Calyx 1–1.8 mm long at anthesis, pubescent, very shortly lobed; fruiting calyx 2.5–3 mm long, shortly tubular, 3 posterior lobes small, triangular, anterior lip blunt, ± emarginate

Morphology Reproductive morphology Flowers Corolla

Corolla bluish mauve, 3 mm long

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens exserted 1.5 mm

Morphology Reproductive morphology Fruits

Nutlets subcylindrical, 0.9 × 0.4–0.5 mm, glabrous.

Ecology

Wet grassland with pools of water in valley bottom; 1700–1800 m

Conservation

Only collected twice in Tanzania and only a few records from the Katanga, northern Zambia and northern Malawi, easily overlooked but also probably uncommon.

Note

Provisionally kept separate from P. coeruleum (R.E.Fr.) A.J.Paton, known only from the type gathering from near Mansa in northern Zambia, a similarly aquatic plant but with the submerged leaves pinnatisect and with hairs in the throat of the corolla. Limniboza lisowskiana was segregated from L. dilungensis principally on account of its ternate leaves, but opposite and ternate leaves are now known from different populations in the Upemba National Park and also occur sporadically in Tanzania and Malawi without any correlated character differences.

Distribution

Range: Congo-Kinshasa (Katanga), northern Zambia and northern Malawi Flora districts: T4