BALFOUR AND SMITH—MOULTONIA. 353 
Hook., we find within its seed at the period when it is ripe 
the protocorm of the embryo as an elongated ovoid body show- 
ing towards the apical end two lateral outgrowths of equal size 
—the cotyledons. There is no trace of a primordium of a primary 
root, nor of a plumular bud, and there never is. When germina- 
tion takes place, the whole surface of the protocorm becomes 
covered with absorptive hairs. One of the cotyledons is arrested 
in growth, the other elongates and growing rapidly by basal 
intercalary growth forms in time a broad green lamina without 
stalk. Soon a series of adventitious roots develop from the 
hypocotyl and also from the cotyledon base. The top of the 
hypocotyl where the cotyledons are does not in this species show 
much growth in length, and the cotyledons remain about the 
same level. Soon the smaller arrested one withers and dies off, 
so that the whole vegetative organisation of the plant is an 
enlarged green cotyledon with a basal portion of hypocotyl and 
adventitious rootlets. Year by year the intercalary growth of 
the cotyledon proceeds and further rootlets are formed. That 
is the whole mature vegetative plant. If at an early period the 
enlarging 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 
s* Unifoliate ’’ Streptocarpi. 
At flowering period the inflorescence takes origin in the 
hypocotyl 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 
hypocotyl 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 hypocotyl 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 hypocotyl. The figure of Acanthonema strigosum, 
Hook. f., in the Botanical Magazine (1862), t. 5339, indicates a 
like history of development in that species. 
Take now the case of S. Rexi, Lindl., as described by Dickie 
(with which that of S. primuloides, Dickie, conforms). Here the 
development starts as in the preceding case, but the top of the 
hypocotyl on the side next and below one of the cotyledons 
