Geissorhiza namaquamontana, 2017

Goldblatt, P. & Manning, J. C., 2017, A review of the Geissorhiza namaquensis (Iridaceae: Crocoideae) group with the new species G. namaquamontana from Northern Cape, South Africa *, South African Journal of Botany 111, pp. 299-301 : 300-301

2. G. namaquamontana Goldblatt & J.C. Manning , sp. nov.

Type: South Africa, Northern Cape, 3017 (Hondeklipbaai): Grootberg, 21 km SW of Kamieskroon, mid to upper south slopes NE of Farm Naries, seasonally damp soils at base and between granite boulders, locally common, 700–860 m, (–BB), 28 Sep 2016, Helme 8822 (NBG) ( Figs. 1 and 2 ).

Plants 80–160(–250) mm high. Corm ± globose, slightly asymmetric with one side obliquely flattened below; tunics dark brown, imbricate, notched below into ± regular segments, drawn into points above. Stem suberect or inclined, flexed at base of spike, puberulous, simple or 1- or 2-branched. Leaves 3 or 4, rarely 5 if plants with more than a single branch, lower 2 basal, ± as long as stem, 2–4 mm wide, remaining leaves cauline, 1.5–3.0 mm wide, sheathing below, shorter than basal, blades narrowly lanceolate, evidently flat but margins raised and narrowly winged, main vein also raised, margins and edges of main vein and sometimes secondary veins ciliate. Spike inclined, flexuouse, 1- to 3(5)-flowered; bracts green below, dry distally, often turning brown near tips, outer subacute, margins membranous, 7–10 mm long, inner slightly shorter. Flowers actinomorphic, salver-shaped, blue, base of tepals and throat white; perianth tube cylindric, widening near throat, 6–7 mm long, shortly exceeding bracts; tepals narrowly lanceolate, (6–)8–10 × 1–2 mm. Filaments erect, equal, 4–5 mm long; anthers 2–3 mm long, white or yellow; pollen white or yellow. Style dividing opposite middle to apex of anthers, often tilted downward, branches ± 1 mm long. Capsules ovoid, 3(–4) mm long. Seeds unknown. Flowering time: mid September to mid October.

Distribution and ecology: restricted to upper elevations above 700 m in the Kamiesberg near Leliefontein and on Rooiberg, and on Grootberg to the west; in renosterveld vegetation on granite outcrops and granitic sands, sometimes in seeps on moss pads.

Diagnosis: like those of the other members of the G. namaquensis group, the leaves of G. namaquamontana are narrowly sword-shaped to nearly linear with the margins narrowly winged and ciliate and the main vein and sometimes a second pair of veins raised and similarly ciliate. It is distinguished from G. namaquensis by the smaller flowers, with shorter tube, 6–7 mm long, tepals (6–)8–10 × 1.5–2.0 mm, and shorter stamens with filaments 4–5 mm long and anthers 2–3 mm long ( Table 1 ).

Although G. namaquamontana usually has four leaves, some plants have only three leaves and one individual from Grootberg with multiple branches has a small fifth leaf. The point of division on the style varies, from opposite the middle to upper third of the anthers in the two Kamiesberg populations but opposite or shortly above the anther apices in the Grootberg plants. The style branches in both sets of populations are short, ± 1 mm long. The Grootberg plants have white anthers and pollen but a note on Helme 3310 from the Kamiesberg indicates that the anthers and pollen are yellow. Lacking additional material we do not know how to assess the significance of the differences between the Kamiesberg and Grootberg plants. Additional field work in Namaqualand is needed.

Additional specimens seen

South Africa. NORTHERN CAPE. 3018 (Kamiesberg): foot of the mountain overlooking Leliefontein, sandy, stony ground, poorly drained (–AC), 12 Oct 1981, Le Roux & Ramsey 672 (NBG, PRE); Rooiberg Massif, neck just west of Pramkop, well drained loam, deep blue, (–AC), 14 Oct 2004, Helme 3310 (NBG).

Figures

Fig. 1. Geissorhiza namaquamontana, Rooiberg, Helme 3310 (NBG). Photograph: Nick Helme.

Fig. 2. Distribution of Geissorhiza namaquamontana (●) and G.namaquensis (○).