Peliostomum junceum (Hiern) Kolberg & van Slageren

Kolberg H., van Salgeren M. 2016. A synopsis of Aptosimum and Peliostomum (Scrophulariaceae) in Namibia, including the description of a new species, Aptosimum radiatum, and keys to all accepted species. Kew Bulletin 71:16. DOI 10.1007/S12225-016-9628-7

Conservation

Based on the few specimens available, the evaluation here is LC for Namibia. Under criterion B both the EOO and AOO are within that for the CR category, but none of the other criteria is met to qualify for a threatened status (IUCN 2012, 2013). Under criterion D, the species would also qualify for VU but these evaluations must be seen against the background of using only two Namibian specimens. The species is probably more widespread but difficult to find and occurs in parts of Namibia that are undercollected. The status in South Africa is LC (SANBI 2014).

Distribution

Africa: Botswana, Namibia, South Africa.

Ecology

Occurring in sandy soil of the Kalahari savanna vegetation type (Mendelsohn et al. 2010). Found in the undefined area between the Kalahari Sands in the south and Zambesian Domain in the north of Craven (2009). Altitude: c. 1500 m.

Morphology General Habit

Shrub, erect, rigid, much-branched, virgate, 8 – 55 cm tall, not spinescent

Morphology Leaves

Leaves sparse, mostly absent or reduced to c. 2 mm long scales, linear to narrowly obovate-oblong, 8 (– 15) × 0.3 – 0.5 mm, glabrous or nearly so; apex obtuse; base subsessile

Morphology Reproductive morphology Flowers

Flowers solitary, axillary, pedicellate; pedicels 1 – 6 mm long, glabrous; bracteoles filiform, to 1 mm long

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens four; filaments subequal in length; anthers equal, long-ciliate

Morphology Reproductive morphology Flowers Calyx

Calyx lobed to base; lobes linear to linear-lanceolate, 2 – 5 mm long, minutely puberulous or glabrous outside, minutely glandular-pubescent inside

Morphology Reproductive morphology Flowers Corolla

Corolla 12 – 18 mm long, minutely stipitate-glandular to glabrous outside; contracted part of tube exceeding calyx, gradually widening, pale purplish-blue to white with purple venation outside; lobes circular to ovate, to 5.5 mm diam., inside purplish-blue, darker patch at base

Morphology Reproductive morphology Fruits

Capsule ovoid-conical, slightly compressed, 5 – 8 × 2 – 3 mm; apex subobtuse or scarcely acute

Morphology Reproductive morphology Seeds

Seed not observed.

Morphology Stem

Stems slender, glabrous to minutely puberulous, somewhat herbaceous, ribbed, angular towards apex; smooth, woody-corky, white towards base

Note

This species has been recorded in the literature only for Botswana and South Africa (Smithies & Ready 2003) but was found recently in Namibia as well. Philcox (1985) considered this taxon sufficiently different from Peliostomum leucorrhizum to elevate var. junceum of Hiern (1904) to specific level but at the same time transferred it to Aptosimum. Following our decision to uphold Peliostomum and Aptosimum as separate genera, the capsule morphology places this species in the genus Peliostomum, necessitating a change of name here.

Phenology

Flowering and fruiting throughout the year. Peak flowering and fruiting: March – April.

Type

Type: [Botswana] Bechuanaland, Chooi desert [between Last-Water Station and Desert Station, Kalahari], Burchell 2338 (holotype K-410923!).