282 MOULTONIA : A NEW BORNEAN GESNERACEOUS GENUS. 
arrested one withers and dies off, so that the whole vegeta¬ 
tive organisation of the plant is an enlarged green cotyledon 
with a basal portion of hypoeotyl and adventitious rootlets. 
Year by year the intercalary growth of the cotyledon pro¬ 
ceeds and further rootlets are formed. That is the whole 
mature vegetative plant. If at an early period the enlarg¬ 
ing cotyledon be removed, the arrested one opposite to it 
on the protocorm may develop into the same form. Here 
there is never a vegetative epicotyl, never a primary root. 
The vegetative body is a persistently growing extension of 
the embryonic state. A like explanation covers the case 
of Lemna amongst Monocotyls—only there the embryonic 
form repeats itself in successive branchings. 
This is the type of what in systematic works is named 
the “ Unifoliate ” Streptocarpi. 
At flowering period the inflorescence takes origin in the 
hypoeotyl within the sinus at the base of the enlarged 
cotyledon, and develops a scapose axis or scapose axes with 
many flowers in biparous cymose branching. It never 
spreads over the laminar area. Meristematic activity 
seems to be located in the hypoeotyl at the base of the 
cotyledonary lamina. How exactly the flower-axis arises 
has not been really observed in this species. We do not 
yet know whether the apex of the hypoeotyl forms a 
primordium which can be interpreted as a postponed 
plumular bud with destiny of flower production only, or 
whether the origin of the inflorescence is spread over a 
wider linear or broader area of the hypoeotyl. The figure 
of Acanthonema strigosum , Hook, f., in the Botanical Maga¬ 
zine (1862), t. 5889, indicates a like history of development 
in that species. 
Take now the case of 8. Rexii , Lindl., as described by 
Dickie (with which that of S. primuloides , Dickie, con¬ 
forms). Here the development starts as in the preceding 
case, but the top of the hypoeotyl on the side next and 
below one of the cotyledons grows out for a short distance 
so that the two cotyledons are separated by a length of 
hypoeotyl. The cotyledon left behind is the arrested one. 
The other enlarges, and a cursory examination of a seed¬ 
ling at this stage might suggest the presence of two coty¬ 
ledons : one sessile small, and one petiolate large. The 
apparent petiole—and it is so called by Hielscher—is really 
the hypoeotyl. When S. Rexii , Lindl., flowers it forms 
one-flowered scapes, and these take origin close to the 
sinus of the cotyledonary lamina from the hypoeotyl 
