Scrophulariaceae - Scrophularioideae - Hemimerideae - Diascia Link & Otto
Description:
Herbs, annual or perennial; stems usually slender, diffuse or erect, sometimes rigid
Leaves opposite or rosulate at base, with upper ones sometimes alternate, mostly petiolate, rarely sessile, variously shaped, from linear to suborbicular or sometimes oblanceolate to obovate, margins usually variously dentate, sometimes repand, pinnatifid or pinnatisect, rarely entire, usually glabrous; upper leaves often somewhat different
Flowers solitary, axillary or subfasciculate, or in terminal racemes, bracteate
Calyx 5-lobed; segments lanceolate, ovate or oblong, somewhat imbricate, slightly accrescent in fruit
Corolla usually tubular, bilabiate; tube very short, sometimes invaginated or obsolete; limb flattened, rotate or concave; posterior lip bi- or quadrifid, exterior in bud; anterior lip trifid or simple, middle or only lobe often emarginate, lobes ± rounded; throat usually produced below anterior lip into 2 (rarely 1 or 0) pits, pouches, or spurs wherein oil-secreting trichomes are found in several species; windows (patches of translucent material) usually present, either at base of lateral corolla lobes, associated with openings to pouches or spurs, or central at base of upper lip, and there sometimes split into 2 contiguous or separate parts; very rarely windows absent; central posterior window varies in form from ± flat to pouched or drawn out into a short hollow cone
Stamens (2)4, didynamous, arising in mouth of corolla tube; posterior pair with anthers; anterior pair usually bent near base, passing round posterior pair and coming to be in posterior position, rarely with anthers 0; some or all filaments broadened, sometimes with a projecting appendage; anthers bithecate but 1-celled as thecae confluent, usually cohering in pairs; staminodes 0(2)
Ovary bilocular, usually ovoid; ovules many; style simple, terete, shorter or somewhat longer than ovary; stigma simple or capitate
Fruit an obliquely ovoid, subglobose or elongated, obtuse, septicidal capsule, not or scarcely compressed; valves inflexed at lateral margins, entire or emarginate
Seeds many, brown, usually curved, often with hollow on ventral side filled with ± cup-shaped or bulbous outgrowth of seed coat with various apertures, usually ribbed and not winged, sometimes pitted or reticulate and/or winged, rarely straight and/or smooth to granulate or muricate
x = 9 (B-chromosomes - 1 report, aneuploids, polyploidy)
Nomenclature:
Diascia Link & Otto
Link & Otto: t. 7 (1820)
Hiern: 139 (1904)
Hilliard & Burtt: 269 (1984)
Steiner & Whitehead: 259 (1988)
Steiner: 175 (1990)
Steiner: 13 (1992a)
Steiner: 39 (1992b)
Steiner: 202 (1992c)
Steiner: 72 (1995)
Steiner: 63 (1996)
Steiner: 223 (1999)
Chamaecrypta Schltr. & Diels
Schlechter & Diels: 787 (1942)
Distribution & Notes:
Southern Africa: Species ± 60, widespread, few in Namibia and Free State, more in KwaZulu-Natal, Lesotho, Northern, Western and Eastern Cape, with mostly perennial species in the east and annual ones in the west
HILLIARD, O.M. & BURTT, B.L. 1984. A revision of Diascia section Racemosae. Journal of South African Botany 50
LINK. J.H.F. & OTTO, C.F. 1820. Icones plantarum selectarum 1. Published by the authors, Hamburg
SCHLECHTER, R. & DIELS, L. 1942. Zwei neue Scrophulariaceen aus dem Kapland. Notizblatt des Botanischen Gartens und Museums zu Berlin 15
STEINER, K.E. 1990. The Diascia (Scrophulariaceae) window: an orientation cue for oil-collecting bees. Botanical Journal of the Linnean Society 102
STEINER, K.E. 1992a. Three new species of Diascia (Scrophulariaceae) from the western Cape. Bothalia 22
STEINER, K.E. 1992b. Two new Diascia species (Scrophulariaceae) from the Little Karoo. South African Journal of Botany 58
STEINER, K.E. 1992c. Two new Diascia (Scrophulariaceae) species from the Nieuwoudtville area, western Cape. South African Journal of Botany 58
STEINER, K.E. 1995. Three new Diascia species from arid areas of the Western and Northern Cape provinces, South Africa. South African Journal of Botany 61
STEINER, K.E. 1996. Chromosome numbers and relationships in tribe Hemimerideae (Scrophulariaceae). Systematic Botany 21
STEINER, K.E. 1999. A new species of Diascia (Scrophulariaceae) from the Eastern Cape (South Africa), with notes on other members of the genus in that region. South African Journal of Botany 65
STEINER, K.E. & WHITEHEAD, V.B. (1988). The association between oil-producing flowers and oil-collecting bees in the Drakensberg of southern Africa. In P. Goldblatt and P. Lowry (eds.), Modern systematic studies in African botany. Monographs in Systematic Botany, Missouri Botanical Garden 25
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