BY PROF. BAYLEY BALFOUR AND W. W. SMITH. 
288 
meristem tissue in a “ simple tangential row.” Here we 
have the case of S. 'polyanthus over again, only that the 
elongation of the hypocotyl has created the appearance of 
a petiole, and so the flower-axis seems to come from where 
an apparent petiole joins a lamina. This is not all, how¬ 
ever. In S. Rexii , LindL, there appears at the cotyledonary 
sinus a cluster of stalked leaf-like structures. These form 
a sort of rosette and are characteristic of the “ Rosulate ” 
Streptocarpi. The published accounts of their origin are 
vague in terms, and their relation to the inflorescence is 
not clear. They are said to come off alternately from a 
whole series of centres, whilst the inflorescences are 
developed in a simple basifugal row. We are in no better 
case here than with S. polyanthus, Hook., for the determi¬ 
nation of the morphological relationship of these later 
vegetative structures and of the inflorescence to the proto- 
corm. All we can recognise is that there is a vegetative 
organisation superposed upon the condition that is per¬ 
manent in S. polyanthus , Hook. For its reconciliation 
with normal plumular development further investigation is 
required. 
Then we have a state of further differentiation in S. 
caulescens , Yatke, as Hickson showed, typical of the whole 
series of “ Streptocarpi Caulescentes.” Here the same 
general lines of early development of the protocorm are 
followed, and there is an elongation of the hypocotyl 
between the cotyledons, the upper of which is the larger. 
This upper cotyledon does not reach extravagant size; it 
has quite the appearance of a petiolate cotyledon coming 
off from the hypocotyl. From the hypocotyl and in appa¬ 
rent upward continuation of it ascends an axis like an 
ordinary epicotylar noded axis bearing foliage-leaves which 
are like the larger cotyledon in form. How this axis 
arises, if from a plumular bud or no, is not described. Its 
appearance suggests such normal evolution as occurs in 
many other Gesneraceae. 
The suggestions conveyed in the construction of these 
Streptocarpi have led us to the interpretation we have 
predicated for Moultonia. One may suppose that the 
hypocotyl below an upper enlarged cotyledon has grown 
out to form the stalk with the lamina of the cotyledon at 
its end, and that the inflorescence meristem, instead of 
being strictly limited to an area at the base of the coty¬ 
ledon, is spread along the hypocotyl and also along the 
lamina. 
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