e-Key v3 - Mesembryanthemaceae Fruit Types
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Interactive keys to the identification of seed plants of southern Africa using keys based on plant morphology.
  • With few exceptions, loculicidal, hygrochastic capsules, which repeatedly open when wet, and close when dry, are characteristic of the Mesembryanthemaceae . Schwantes' (1952) early work on mesemb fruits was refined by Hartmann (1988) who described nine unique functional syndromes for fruit capsules of the entire group. Fruit types are here arranged in alphabetical order
  • Apatesia type
    • Expanding sheet predominant but expanding properties reduced
    • Covering membranes absent
    • Valve wings absent
  • Delosperma type
    • Expanding keels ± radial, distinct from expanding sheets
    • Covering membranes absent or vestigial, derived entirely from inner endocarpal valvar tissue declining into the empty locules
    • Closing bodies absent
    • Valve wings broad
  • Drosanthemum type
    • Expanding keel distinct from expanding sheet, divergent over the valves with a ± free, radial elongation, the keel-awn broadened towards the centre of the valve
    • Covering membranes compound: proximal part derived from valvar endocarp including the epidermis, marginal parts derived from inner endocarpal tissue (the complementary epidermis forms the extension of the expanding keel); persistent in shape, translucent, ± flat, and of ± equal diameter throughout
    • Closing bodies absent
    • Valve wings broad
  • Lampranthus type
    • Expanding keels divergent, sometimes broadened
    • Covering membranes rigid, stout, of persistent convex shape, with a distinct recurved rim above and a closing ledge below their distal ends
    • Closing bodies absent but with bunches of sterile funicular hairs at exits of locules
    • Valve wings present or absent
  • Leipoldtia type
    • Expanding keels divergent, with distinct radial awns, not broadened; expanding sheets present
    • Covering membranes persistent, resilient, of permanent concave shape with curved radial upper edges, distally and distinctly recurved; endocarp forming a ± pronounced boss or ledge below the expanding keel
    • Closing bodies large, distinctly stalked, outer layers sclerenchymatous, inner corky tissue well developed
    • Valve wings broad
  • Mesembryanthemum type
    • Expanding keels strictly septal, radial on valves and reaching the central axis (in closed fruit)
    • Expanding sheets absent
    • Covering membranes absent
    • Closing bodies absent
    • Valve wings broad, entirely connate to valves
  • Mitrophyllum type
    • Expanding sheets dominant, transgrading into an expanding keel in central valvar position; consequently expanding keels ± flat and appressed to valves
    • Covering membranes derived from parts of valvar endocarp that do not develop into expanding tissue, simple, translucent, persistent in shape, ± flat with an inconspicuous marginal edge from inner endocarpal tissue
    • Closing bodies infrequently developed from a broad base in the shape of a ledge, boss or bracket consisting of spongy cutinised tissue situated above the placenta and below the expanding sheet which diminishes on the closing bodies or bosses
    • Valve wings broad
  • Ruschia type
    • Expanding keels widely divergent, short, without a radial extension, not higher than broad
    • Covering membranes stout, of persistent convex shape with distal upright rims and prominent closing rodlets below
    • Closing bodies small, rodlet-shaped, each with a small central corky part
    • Valve wings narrow or absent
  • Titanopsis type
    • Expanding keels distinct from expanding sheets, divergent and broadened towards the centre of the valve
    • Covering membranes compound (as in the Drosanthemum type), but central parts thicker than marginal parts, and boundaries slightly raised into low ridges, and marginal parts bent into the empty locules, translucent and descending centrifugally; extension of very floppy, thin covering membranes reduced
    • Closing bodies absent or small
    • Valve wings broad

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