Duosperma tanzaniense Vollesen

Acanthaceae (part 2), Kaj Vollesen. Flora of Tropical East Africa. 2008

Type

Type: Tanzania, Mbeya District: Poroto Mts, Chimala, Bidgood, Congdon & Vollesen 2105 (K!, holo.; BR!, C!, CAS!, DSM!, K!, NHT!, UPS!, iso.)

Morphology General Habit

Perennial or shrubby herb with erect (rarely decumbent) branched stems from woody rootstock; stems to 1(–1.5) m tall, glabrous to bifariously sericeous (hairs retrorse) or puberulous and with (rarely without) sparse to dense broad glossy hairs to 1.5 mm long; bark eventually peeling in large papery strips

Morphology Leaves

Leaves ovate to elliptic, largest 4.5–11 × 2–4.5 cm, more than twice as long as wide, apex subacute to acuminate (rarely rounded), base attenuate to truncate, decurrent to a distinct petiole to 1(–2) cm long, with sparse long broad hairs, below densest (or only) along veins, above uniformly dispersed, rarely sericeous-pubescent or subglabrous, petiole distinctly ciliate with broad glossy hairs, margin crenate to dentate, tertiary veins distinctly raised beneath; stipule sheath to 1 mm long, ciliate and usually hairy

Morphology Reproductive morphology Flowers

Flowers subsessile, in many-flowered well separated condensed axillary cymes (rarely 1- or few-flowered); peduncles 1–3(–4) mm long, glabrous to puberulous or sericeous; outer bracts foliaceous, to 2.2 cm long; inner bracts and bracteoles lanceolate to ovate, to 1.5 cm long, acuminate to cuspidate, subglabrous to puberulent, without or with sparse to dense long broad glossy hairs, ciliate

Morphology Reproductive morphology Flowers Calyx

Calyx 8–15(–18 in fruit) mm long, glabrous (rarely puberulous or sparsely so), tube and basal part of teeth also with (rarely without) sparse to dense long (to 1.5 mm) broad glossy hairs, apical part of teeth with shorter hairs, sometimes with a few stalked capitate glands near base of tube, tube 4–7 mm long; teeth lanceolate to narrowly triangular, acuminate to cuspidate, dorsal 5–8 mm long (same length or longer than tube), ventral 4–7 mm long of which the free part 2–5 mm long

Morphology Reproductive morphology Flowers Corolla

Corolla white with red to purple lines or patches on lower lip, 12–17(–20) mm long, finely sericeous-puberulous or sparsely so; tube 8–10(–12) mm long of which the throat 2–4(–5) mm long; lips 4–9 mm long; lobes oblong to obovate, 1.5–4(–6) mm wide, truncate to retuse; palate with or without scattered to dense stiff hairs. Filaments 2–5 mm long, with scattered hairs near base; anthers 1–2 mm long, thecae rounded or finely apiculate at base, connective with scattered to dense glands. Stigma lobes subequal or dorsal distinctly shorter

Morphology Reproductive morphology Fruits

Immature capsule 7–8 mm long, obovoid

Morphology Reproductive morphology Seeds

Seed not seen

Ecology

Brachystegia woodland on brown to red gritty to stony soil on rocky slopes, Combretum bushland on limestone slope, Acacia woodland, grassland on old cultivations; (800–)1000–1650(–1800) m

Distribution

Range: Not known elsewhere Flora districts: T4 T5 T7 T8

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/48153859/48154617

Conservation

LC - least concern