Tropicos | Name - Lapeirousia fabricii (D. Delaroche) Ker Gawl.

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Iridaceae in sub-Saharan Africa

African Iridaceae > Iridaceae > Lapeirousia > Lapeirousia fabricii

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Lapeirousia fabricii (D. Delaroche) Ker Gawl.

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Project Name Data (Last Modified On 6/6/2016)

Acceptance : Accepted

Taxon Profile (Last Modified On 6/20/2016)

Description: Plants mostly 100–250 mm high, usually 4–6-branched; stem compressed, angled and 2-winged, wings irregularly serrated. Corm 10–15 mm diam., broadly obconic; tunics brown, lightly ridged vertically, basal rim with short, spreading spines 1–2 mm long. Leaves several, lowermost longest, linear to falcate, ribbed, shorter or longer than stem; remaining leaves cauline, progressively shorter, not or barely ribbed, often subtending branches, upper becoming bract-like. Inflorescences (2–)4–8-flowered spikes; outer bract green or flushed red, (10–)14–20(–25) mm long, keeled, acute, margins often reddish, keel crisped or minutely serrate; inner bract transparent with 2 green keels,1/2 to 2/3 as long as outer, forked at apex. Flowers zygomorphic, white to pale yellow or beige, purple or rarely pink, usually red or pink on reverse of tepals and tube, lower tepals each with red spot in midline, throat marked with fine red lines inside and out, decurrent on lower part of tube; perianth tube obliquely funnel-shaped, 30–65 mm long, narrow and cylindric below, abruptly expanded into wide upper part up to 10 mm long; tepals usually unequal (rarely subequal), all straight below and continuing upper part of tube as a tepal cup, then spreading horizontally, upper 3 largest, 20–24 × 7–12 (subsp. fabricii), 15–18 × 7–10 mm (subspp. compressa and purpurascens), lower 3 with claws ± 4 mm long, limbs 10–20 × 3–7.5 mm, each often with short, claw bearing claw-like cusp arching over limb base. Stamens unilateral, arched; filaments 6–10 mm long (subspp. compressa and purpurascens) or 10–17 mm long (subsp. fabricii), exserted 3–7 mm from upper part of tube and 1–3 mm from tepal cup; anthers 3–5 mm long, dark purple; pollen purple. Style arching over stamens; branches 3–5 mm long, usually dividing near middle of anthers, forked for 1/2 their length, recurved. Capsules oblong, 10–12 mm long, apices of locules forming ear-like lobes decurrent on low locular ridges. Seeds globose, flattened at chalazal end, 1.2–1.3 mm diam. Chromosome number 2n = 16. Flowering time: August to October depending on subspecies, usually fairly late in spring.

Country: South Africa

South African Province: Northern Cape, Western Cape

Distribution and ecology: widespread in the drier, western half of Western Cape and common in Namaqualand in Northern Cape, extending from near Steinkopf in the north to Malmesbury in the south and inland to the western edges of the Tanqua Basin along the eastern foothills of the Swartruggens and Cedarberg; most often in rocky sandstone or granite derived soils but occasionally in deep, hard sand, or in crevices in rocks.

Diagnosis: the flowers of Lapeirousia fabricii are among the largest in the genus, with its long perianth tube and often wide throat. The perianth tube ranges from 30–65 mm long and is usually expanded in the upper 5–10 mm in a short to long cup or gullet. The tepals are shortly clawed, particularly the lower three, which are united basally for ± 2 mm and the erect claws form the upper part of the floral cup. When fully open the lower and sometimes the upper tepal limbs spread at right angles to the tube, or the dorsal is suberect. The lower tepal claws often bear claw-like cusps that arch forward over the limb bases; these cusps are sometimes absent and represented by thickened median ridges. Vegetatively, L. fabricii has distinctive flattened, narrowly winged stems, the wings usually minutely crisped or serrated. The well developed outer floral bracts are ribbed and have crisped to serrated keels.

General Notes: variation across the range of Lapeirousia fabricii has prompted us to recognize three subspecies, the most common and widespread of which, subsp. fabricii, is centred in the northern half of its range. It has predominantly pale yellow to beige flowers with red markings, lower tepals about half as wide as the dorsal, and a perianth tube mostly 50–65 mm long with a wide, deep throat up to 10 mm long. South and west of the Olifants River Mtns, plants treated as subsp. compressa have white or pale pink flowers with pink markings, lower tepals not or only slightly narrower than the dorsal, a perianth tube 30–45 mm long, and a short, relatively narrow throat usually only ± 5 mm long. The third subspecies, subsp. purpurascens, is restricted to the dry interior valleys of the Cedarberg and northern Swartruggens and has blue-purple flowers, lower tepals ± 1/2 as wide as the upper and a perianth tube 30–45 mm long. Its flowers also differ from the typical in having a relatively shallow gullet ± 5 mm deep, and correspondingly shorter filaments 7–9 mm long. The long-tubed flowers of the typical subspecies are known to be pollinated by long-proboscid flies and the same pollination strategy is inferred for subsp. compressa and subsp. purpurea, probably using a different fly species in the latter.