e-Key v3 - Roridulaceae
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Interactive keys to the identification of seed plants of southern Africa using keys based on plant morphology.

DICOTYLEDON - DILLENIIDAE - ERICALES - Roridulaceae

Compiled by M. Jordaan

Description :

  • Sparsely branched, woody, glanduliferous, viscid shrublets or shrubs, with leaves aggregated near tips of branches, trapping but not absorbing contents of insects; root system poorly developed
  • Leaves alternate, simple, sessile, flat, linear, lower soon dropping off, margins smooth or with long, filiform teeth, furnished with long, immovable, gland-tipped tentacles, yellowish green; stipules 0
  • Inflorescence a few-flowered panicle, pedunculate, flowers solitary or aggregated in axils of linear bracts; pedicels short or long
  • Flowers bisexual, regular, hypogynous
  • Sepals 5, green, free or fused at base, imbricate, glanduliferous, persistent
  • Petals 5, free, imbricate, broadly ovate or obovate, entire, glabrous, purple or crimson to nearly white, persistent or deciduous
  • Stamens 5, opposite sepals; filaments distinct, erect; anthers elongate, introrse, incurved in bud, subtended by a basal swelling containing a nectariferous cavity and 2 semifree thecae which open by apical pores, suddenly springing upright and shedding pollen when touched
  • Ovary superior, 3-locular, each locule with 1-4 ovules on an axillary placenta; style simple; stigma apical
  • Fruit a 3-valved loculicidal capsule
  • Seeds fairly large, warty or honeycombed, becoming mucilaginous when moistened, rich in endosperm

Classification Notes: Roridula is sometimes combined with Byblis in the Australian family Byblidaceae , e.g. Hutchinson (1959), Cronquist (1981) and Mabberley (1997)

Nomenclature:

  • Roridulaceae
    • Endlicher: 906 (1839) as Droseraceae
    • Sonder: 75 (1860)
    • Drude: 268 (1891) as Droseraceae : Roriduleae
    • Marloth: 26 (1925)
    • Diels: 346 (1930)
    • Obermeyer: 202 (1970)
    • Dahlgren & Van Wyk: 61 (1988)

Distribution & Notes:

  • Southern Africa : Monogeneric with 2 species, endemic to the Western Cape

References:

  • CRONQUIST, A. 1981. An integrated system of classification of flowering plants . Columbia University Press, New York
  • DAHLGREN, R. & VAN WYK, A.E. 1988. Structures and relationships of families endemic or centered in southern Africa. Monographs in Systematic Botany from the Missouri Botanical Garden 25
  • DIELS, L. 1930. Roridulaceae . Die natürlichen Pflanzenfamilien , edn 2, 18a
  • DRUDE, O. 1891. Droseraceae . Roriduleae . Die natürlichen Pflanzenfamilien 3,2
  • ENDLICHER, S.L. 1839. Droseraceae . Genera plantarum secundum ordines naturales disposita 2. Beck, Vienna
  • HUTCHINSON, J. 1959. Byblidaceae . The families of flowering plants . Clarendon Press, Oxford
  • MABBERLEY, D.J. 1997. The plant-book , edn 2. Cambridge University Press, Cambridge
  • MARLOTH, R. 1925. Roridulaceae . The flora of South Africa 2. Darter, Cape Town
  • OBERMEYER, A.A. 1970. Roridulaceae . Flora of southern Africa 13
  • SONDER, O.W. 1860. Droseraceae . Flora capensis 1

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