328 BOTANICAL GAZETTE [NOVEMBER 
causes no damaging pressure as does the wedge-shaped blade of a 
scalpel or ordinary razor. The nucellus usually remains within the 
cup-like top of the ovule. Four strokes with a sharp scalpel will 
cut through the nucellus against the stony background and remove 
a piece containing the pollen tubes. Methods for studying the living 
sperms will be given in a second paper. For showing the grosser 
structures of the ovules, sections 4 or 5™™ in thickness were dehy- 
drated and then cleared in xylol. For tracing the vascular bundles, 
the pseudo-stalks of ovules were cut under water and the bases were 
placed in eosin. The outer bundles soon become conspicuous on the 
surface, and the inner bundles are easily traced by removing the 
endosperm and scraping away the greater part of the inner fleshy 
layer of the integument. 
Most of the sections were stained in safranin and gentian-violet; 
some were stained in iron-alum haemotoxylin. Magdala red and 
anilin blue proved to be a good combination, especially for pollen- 
tube structures, and it is quite convenient, since no clearing agent 
is necessary, the slides being taken directly from the absolute alcohol 
and mounted in Venetian turpentine. Overstaining in the Magdala 
red can be corrected, even after the cover glass is in place, by exposing 
the slide to direct sunlight for a short time. 
III. MEGASPOROPHYLLS AND OVULES. 
No other cycad, except Cycas, has such large and leaf-like mega- 
sporophylls as Dioon (figs. 4-6). Both the leaf-like character of 
the megasporophylls and their comparatively loose association in the 
cone are more suggestive of Cycas than of Zamia or Ceratozamia, 
which are the geographical neighbors of Dioon. The remaiing 
occidental cycad, Microcycas, is too imperfectly described to allow 
any comparison of the cones, 
In Dioon the sporophylls at the base of the ovulate cone are 
yellowish or greenish, with little hair except along the central portion 
of the back. There are four or five turns of the spiral of these spore 
phylls, followed by one or two turns of somewhat hairy sporophylls. 
The remaining sporophylls are densely covered with long brown 
hairs, the lower ones on the back and edges and a small portion of 
the upper part of the inner face, and the rest not only upon the back 
