Tropicos | Name - !Geissorhiza lapidosa Goldblatt & J.C. Manning

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Iridaceae in sub-Saharan Africa

African Iridaceae > Iridaceae > Geissorhiza > Geissorhiza lapidosa

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!Geissorhiza lapidosa Goldblatt & J.C. Manning

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Project Name Data (Last Modified On 9/8/2016)

Acceptance : Accepted

Taxon Profile (Last Modified On 9/8/2016)

Description: Plants ± acaulescent, 20‑40 mm high. Corm obliquely ovoid with narrow flat side, 4–5 mm diam., tunics woody, dark, blackish, concentric. Stem smooth, flushed red, not or barely extending above ground, unbranched. Leaves 4, lower 2 basal, third leaf inserted at or shortly above ground, linear-falcate, exceeding spike, 0.5–1.0 mm wide, thick and leathery, elliptic in section when fresh, glaucous with margins often reddish, uppermost leaf cauline, entirely sheathing. Spike 1- or 2-flowered; bracts leathery and glaucous flushed reddish but submembranous and finely flecked with brownish red on margins, outer truncate or obscurely tricuspidate, 4–5 mm long, inner as long or slightly shorter, notched at apex. Flowers actinomorphic, rotate, white with outer tepals reddish pink outside; perianth tube funnel-shaped, 2.0–2.5 mm long; tepals oblanceolate, ± 6 × 2 mm. Filaments erect, equal, 3.5–4.0 mm long; anthers 1.5–2.0 mm long, ± white; pollen white. Style dividing opposite lower 1/2 of anthers, branches 1.5–2.0 mm long. Flowering time: November.

Country: South Africa

South African Province: Western Cape

Distribution and ecology: restricted to Goudini Sneeukop in the Du Toits Kloof Mtns in Western Cape; along a narrow band of sandstone pavement at the edge of cliffs in moist seeps draining from a shale sponge overlying the sandstone, a very restricted habitat less than 4 m wide, unusual for the genus. The two known colonies are about 800 m apart in an area regularly covered by snow in winter and spring.

Diagnosis: distinguished by its small size and underground stem, Geissorhiza lapidosa has a corm with concentric tunics and smooth, ± plane, falcate leaves. It differs from other dwarf species of subg. Weihea in its high mountain habitat and unusual leathery, falcate leaves at most 1 mm wide. The short-tubed, white flowers have an unusually short style dividing opposite the lower half of the anthers. Similar flowers are found in G. nana and G. setacea, both lowland species: G. nana occurs in renosterveld vegetation in the Overberg between Caledon and Swellendam and has broader, thin-textured leaves up to 2 mm wide and even smaller flowers with the tepals mostly 3–6 mm long, and very short filaments ± 2 mm long; G. setacea grows in seasonally wet places on flat sandy or loamy ground in Western Cape between Gouda and Caledon and has similarly narrow but linear leaves, 0.5–1(–2) mm wide but larger flowers with tepals 6–8 mm long, a longer tube ± 6 mm long, and the style branching opposite the tips of the anthers.