354 BALFOUR AND SMITH—MOULTONIA. 
grows out for a short distance so that the two cotyledons are 
separated by a length of hypocotyl. The cotyledon left behind 
is the arrested one. The other enlarges, and a cursory examina- 
tion of a seedling at this stage might suggest the presence of two 
cotyledons: one sessile small, and one petiolate large. The 
apparent petiole—and it is so called by Hielscher—is really the 
hypocotyl. When S. Rexi, Lindl., flowers it forms one- 
flowered scapes and these take origin close to the sinus of 
the cotyledonary lamina from the hypocotyl meristem tissue 
in a “simple tangential row.” Here we have the case of 
S. polyanthus over again, only that the elongation of the hypo- 
cotyl 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, however. 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. folyanthus, Hook., for the determination of the 
morphological relationship of these later vegetative structures 
and of the inflorescence to the protocorm. All we can recognise 
is that there is a vegetative organisation superposed upon the 
condition that is permanent in S. folyanthus, Hook. For its 
reconciliation with normal plumular development further in- 
vestigation is required. 
en we have a state of further differentiation in S. 
caulescens, Vatke, as Dickson 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 coty- 
ledons 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 apparent 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 appear- 
ance 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 
ape _—— cotyledon has grown out to form the stalk with 
