33$ ZONES AND REGIONS [Pt. Ill, Sect. I 



carpus integrifolia, Covellia lepicarpa, Sterculia rubiginosa, Oreocnida major, 

 Diospyros sp., Averrhoa Bilimbi, and others. The cauliflory is very peculiar in 

 Stelechocarpus Burakol, a small tree belonging to the Anonaceae, for in it the female 

 flowers spring in tufts out of thick warts on the stem, whilst the smaller male flowers 

 shoot out of the axils of leaves that have just fallen from the twigs. In Taxotrophis 

 javanica, on the other hand, I found the male flowers definitely on the stem, but the 

 female flowers in the axils of leaves on young twigs. 



Cauliflory either excludes the formation of flowers on young twigs, as in 

 cases enumerated above, or the flowers may appear on young twigs as well 

 as on the old cortex. Frequently cauliflory appears to be an occasional 

 feature only. 



Among plants that are not exclusively, but are only occasionally cauliflorous, are, 

 for instance, Saurauja pendula, Ficus cuspidata, Capura alata, Medinilla laurifolia, 

 Drimyspermum longifolium, Oreocnida major, Sterculia rubiginosa, Brownea 

 coccinea. 



All possible transitions connect typical cauliflory with the production of 

 flowers on young twigs. Thus a number of species are cauliflorous only 

 on relatively young branches ; for instance Flacourtia inermis, Evodia 

 Batjan. In other cases the flowers appear on the defoliated base of 

 a foliage shoot, the upper part of which bears leaves ; for instance species 

 of Lasianthus, Goniothalamus Tapis, Gonocaryum myrospermum. In 

 a number of herbaceous plants the flowers appear only in the axils of 

 fallen leaves, as in Campelia marginata, Agalmyla staminea, Cyrtandra 

 nemorosa. According to Johow, the flowers of several Sapotaceae occur 

 only on two-year-old defoliated portions of the twigs. 



The separation in space of the vegetative and reproductive functions — 

 for this is the subject under discussion — is exhibited more strikingly than 

 in true cauliflory, wherever certain leafless or very weakly foliaged twigs 

 springing from the main stem or from the thickest branches alone are fertile, 

 whilst the crown remains purely vegetative. Such twigs, for instance, 

 encircle, like lianes, the lofty stem of Couroupita guianensis, and bear 

 spherical fruits as large as one's head. 



In Ficus sp. ' Minahassae ' (Fig. 183), thin whip-like, scale-leaved twigs 

 spring from the main stem and the thickest branches, on which little figs 

 are grouped in small capitula. In Ficus rhizocarpa such twigs spring out 

 close to the ground only l . In Anona rhizantha, which has been investigated 

 by Eichler, the fertile twigs are subterranean at their base and only their 

 flowering tips project above the ground. 



The question has often been raised why cauliflory is so much commoner 



in the tropics than in temperate zones, and the distribution has usually 



been associated with the conditions of pollination. To me it seems most 



probable that it is owing to the weaker development or less degree of 



1 I noticed both species at Buitenzorg. 



