Isoglossa gregorii (S.Moore) Lindau

Flora Zambesiaca Acanthaceae (part 2) by Iain Darbyshire, Kaj Vollesen and Ensermu Kelbessa

Morphology General Habit

Straggling or trailing decumbent perennial herb, 10–100(200) cm tall, rooting at lower nodes.

Morphology Stem

Stems pubescent with mainly retrorse hairs in two opposite lines, later glabrescent.

Morphology Leaves

Leaves ovate, 1.5–12 × 0.8–7.5 cm, base attenuate to rounded, apex (sub)acuminate, margin and midrib pubescent, upper surface and veins beneath sparsely pilose or veins glabrous; lateral veins (4)5–7(8) pairs; petiole 4–60(90) mm long.

Morphology Reproductive morphology Inflorescences

Inflorescence terminal on main and short lateral branches, sometimes with reduced inflorescence in upper leaf axils, spiciform or with 1–2 branches, main axis 2–24 cm long, often curved, cymules subsessile along axes, clustered with bracts imbricate towards apex, ± distantly spaced below at maturity, ± 1-sided, one bract of each pair often sterile; axis retrorse-pubescent in 2 opposite lines or more widespread, sometimes also with scattered glandular and/or long crisped eglandular hairs; bracts often purple towards apex, elliptic to somewhat obovate or basal pairs ovate, 4.5–9 × 2.5–9 mm, apex attenuate to acuminate, glabrous except for inconspicuous short hairs along margin, occasionally with scattered short-stalked glands; bracteoles elliptic-lanceolate, 3–7 mm long.

Morphology Reproductive morphology Flowers Calyx

Calyx lobes tinged purple towards apex, subulate, 3.5–6.5 mm long in flower, extending to 5.5–11 mm in fruit, with short eglandular hairs particularly along margin, often also with scattered glandular hairs and/or long crisped eglandular hairs.

Morphology Reproductive morphology Flowers Corolla

Corolla 7.5–16.5 mm long, pink, mauve or rarely white, with pink to purple markings on palate and throat; largely glabrous or pubescent extrenally on limb and upper tube; tube subcylindrical, (4)5–9.5 mm long, 1–1.5 mm wide at base, 1–2.7 mm at mouth; upper lip hooded, 2.5–6 mm long, lobes reflexed, 0.5–1.5 mm long; lower lip 3–7 mm long, lobes 1.3–2.5 mm long, palate lacking prominent herring-bone patterning.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens attached in upper third of corolla tube; filaments free for 1.5–3.5 mm; anther thecae superposed and subparallel, each 0.65–1.1 mm long.

Morphology Reproductive morphology Fruits

Capsule 7.5–10 mm long, glabous or with minute eglandular hairs, occasionally with scattered glandular and/or long eglandular hairs.

Morphology Reproductive morphology Seeds

Seeds 1.5–2.5 × 1–2 mm, with elongate, glochidiate tubercles most dense towards rim.

Distribution

Also in northeastern D.R. Congo, Uganda, Kenya and Tanzania.

Ecology

Moist montane and submontane forest, including open areas, sometimes by water; 1400–2200 m.

Conservation

Conservation notes: Assessed as Least Concern in F.T.E.A. Uncommon in the Flora region and apparently absent from several seemingly suitable montane areas (e.g. Misuku Hills of Malawi), but widespread and common in the highlands of Kenya and N Tanzania.