The results of my own experiments with mericarp floatation are shown in Table 1, in which mericarps are shown to float for at least 24 hours, long enough to be carried by water over a considerable distance.
The possibility exists that a mucilaginous mericarp might adhere to a fallen leaf, which might then function like a wing for wind dispersal, but this mode of dispersal seems highly unlikely and certainly not typical of a species (van Rheede van Oudtshoorn & van Rooyen, 1999).
Although Weckerle and Rutishauser (2005) have described the structure of the gynoecium and the fruit ontogenesis of nine Paullinieae species including Urvillea ulmacea, detailed descriptions and illustrations concerning the separation system of mericarp and of dehiscence are lacking.
Houssayanthus, Lophostigma and Serjania are characterized by schizocarpic fruit with winged (samaroid) mericarps, Cardiospermum and Urvillea, by papery, inflated capsules, and Paullinia by capsules.
heliotropioides in having sepals tipped with a purple mucro and relatively short petals, but the mericarp
does not resemble either M.
laurifolia in most characters but its mericarp has been modified from the wind-dispersed samara of H.
Unlike most species in the genus, this one is presumably dispersed by water, the wing of the mericarp being reduced to a rudimentary dorsal crest (Fig.
The category of small and soft seeds ([DH.sup.1/2] [less than] 4) comprises 22 species; three species, Bursera graveolens, Cenchrus platyacanthus, and Opuntia echios, constitute the medium category ([DH.sup.1/2] = 9-14); and the third category is represented by a single species, Tribulus cistoides, whose woody mericarp
containing four to six seeds has an average depth-hardness value of 27.
2B in Liu et al., 2006) is 7-winged, and asymmetrically schizocarpic, with three wings (a median and two marginal wings) on one mericarp
, and four wings (two lateral and two marginal) on the other.
The diaspore is a 1.5 x 2 mm spherical mericarp
that does not have any specific way of dispersal except for falling from the mother plant.