358 BOTANICAL GAZETTE [ocTOBER 
connectives have not become so broadened as later, so that the 
individual stamens appear more distinct than the tube shows at 
maturity. The youngest stage where differentiation appears is 
indicated in fig. 14, where hypodermal masses of meristematic cells, 
separated from each other by a double layer of sterile cells, appear 
beneath a distinct, large-celled epidermal layer. At this time the 
ovary chamber is just beginning to show distinctly with the 3 pla- 
centae, which later give rise to the ovules projecting inward. Later 
the individual sporangia show the parietal layer to be but 2 layers 
thick, within which there is a conspicuous tapetum, while outside 
of it is the epidermal layer (fig. 15). The tapetum shows dark 
irregular bodies which may represent waste or reserve material. At 
this stage it is evident in many preparations that not all of the tissue 
originally differentiated as ‘“‘spotogenous”’ is fertile. A number 
of the spores abort, so that in any one section only a few appear 
normal (fig. 16). Often between adjacent cells small oil globules 
appear as extraneous matter, possibly released through changes 
due to degeneration of the spores. 
The microspores are shed from the stamens through a longitu- 
dinal dehiscence of the anther. At the time of shedding one 
division of the microspore nucleus has taken place in such as appear 
functional. The tube and generative nuclei can be distinguished 
quite readily, although often other bits of dark staining material 
are present. 
Germination of pollen grains with formation of fine pollen tubes 
has been observed. By dissection of the style several tubes were 
traced through to the ovary cavity. At this time practically all 
the pollen had been shed from the stamens of the flowers under 
consideration. It seems likely that there is self-pollination as in 
other forms. The contrast with the Euburmannia forms reported 
lies in failure of development of the mass of pollen tubes from the 
microsporangia to the stigma, as reported by Miers and Ernst and 
| BERNARD. The structure would practically bar such a possibility, 
since the greatly developed stamen tube arising from the connec- 
tives usually extends below the level of the stigma. The dehiscence 
of the microsporangia occurs on the face away from the central 
region in which the style is erected, and the pollen falling from the 
