e-Key <span id="jodit_selection_marker_1709025903105_23471537509700613" data-jodit_selection_marker="start" style="line-height: 0; display: none;"></span>v3 - Di<span id="jodit_selection_marker_1709025903105_9092896603217675" data-jodit_selection_marker="end" style="line-height: 0; display: none;"></span>ascia
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Interactive keys to the identification of seed plants of southern Africa using keys based on plant morphology.

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
    • Pollinated mainly by oil-collecting bees

References:

  • HIERN, W.P. 1904. Scrophulariaceæ. Flora capensis 4,2
  • 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