1913] YORK—DENDROPHTHORA 97 
The flower 
The earliest stage obtained in the development of the flower 
shows that it is not axillary in origin, but is initiated by a bulging 
out of the periblem of the inflorescence axis some distance above 
the axil of the subtending bract (figs. 4, 5). The flowers of Rho- 
palocnemis phalloides have a similar origin, as was shown by 
Lotsy (20). Following such a stage, the surrounding tissues of 
the incipient floral 
axis expand rapidly, 
which results in it 
becoming almost 
completely buried 
within the axis of 
the young spike 
(figs. 4, 9). Two 
cycles of floral seg- 
ments develop acro- 
petally on the young 
axis of the flower. 
The outer consists 
of three parts, which 
are the segments of Fic. 12a.—Diag ti 
the perianth; while at AB, fig. 12: m, floral apex or . mamelon”’; ca, carpels; 
s, sepals; c, swollen part of inflorescence axis about 
flower. 


cectinn af A 
al, 
taken 
the inner is com- 
posed of two seg- 
ments, the carpels. The perianth completely covers the apex of 
the floral axis before the carpels have begun to develop (fig. 10). 
The two carpels arise as distinct primordia, and upon elongating 
inclose the moundlike apex of the floral axis between them (fig. 11). 
At this period of development the flower is still sunken in the axis 
of the spike, and its various parts are clearly distinct from one 
another (fig. 12, text fig. 12a). The apical growth of the floral 
axis is never active, and the outer region, composed of torus and 
the basal portion of the carpels, now grows rapidly, and thus the 
axis with the narrow ovarian cavity about it becomes deeply 
sunken within the torus (fig. 13). According to GorBEt (69), 
there is a somewhat similar uprising of the torus and carpels 
