Ammannia uniflora Meijden

de Wilde, W. J. J. O. & Duyfjes, B. E. E., 2014, Ammannia (Lythraceae) in Malesia, Blumea 59 (1), pp. 11-18 : 17

7. Ammannia uniflora Meijden

Ammannia uniflora Meijden (1966) 245,f. 1. — Type: Womersley NGF 15301 (holo L; iso BRI, CANB, LAE).

Decumbent, annual, glabrous herb, c. 10 cm tall, few-branched, rooting at the nodes; stem 4-angular, not or faintly winged. Leaves sessile; lamina subcircular or broadly ovate, 0.3–0.7 by (0.2–) 0.3–0.6 cm, base narrowed into an up to 1 mm long petiole, apex broadly rounded; lateral nerves (1–)3(–4) per side. Inflorescences: flowers solitary, sessile; peduncle absent. Flowers 4-merous; pedicel 1–2 mm long (in fruit to 4 mm long), at base with 2 minute bracteoles; calyx tube glabrous, (narrowly) campanulate, 1.5–2 by 1.5 mm, 8-nerved, lobes suberect, broadly triangular, c. 0.5 mm long, acute, appendages 0.1–0.2 mm long; petals ‘pale blue’ (see note), broadly ovate, 1–1.5 mm long, caducous; stamens inserted at c. 1/3 from the base in the tube, included; ovary glabrous, broadly ellipsoid, c. 1 mm long, style c. 0.5 mm long, placenta central. Capsules greenish, subglobose, c. 1.8 mm diam, included or hardly exserted. Seeds 10–15, brownish, flattened at one side, c. 0.5 mm long.

Distribution — Papua New Guinea (Western Highlands) known from 3 collections: Eichler 18268, WalkerANU 563, Womersley NGF 15301.

Habitat & Ecology — Prostrate herb in peat swamp;c. 2 500 m altitude. Flowering and fruiting from May to August.

Fieldnotes — The stem is recorded as juicy and the petals as pale blue, but it is likely that the colour of the latter is more purplish or pinkish.

Note — According to S.A. Graham (Missouri, in litt.), who examined all three collections known to date, this species belongs in the genus Ammannia . However, its procumbent habit is infrequent in Ammannia s.str., and a similar spreading habit occurs in some Nesaea species, now included in Ammannia . Furthermore, the few and larger seeds are also a-typical. The pollen is of the Ammannia - Nesaea type, although very small (min. 16 by 12 µm) for the genus.