1g2 BOTANICAL GAZETTE [MARCH 
The first protuberance of the sporophyll is brought about by a 
periclinal division of a hypodermal cell in the axial row (jig. 11), 
and later by the growth and division of the hypodermal cells and of 
layers beneath them (jig. 12). The outer layer divides anticlinally, 
but at the tip of the strobilus the divisions are also periclinal. Strobili 
of June 15 show further cell divisions in the young sporophyll and the 
appearance of rudimentary bundles (jig. 13). By July 8 the strobili 
have lengthened to6or8™™. The new sporophylls appear toward the 
apex (fig. g), but there is as yet no differentiation of sori. The strobili 
of July 25, which are 10 to 12™™ long, exclusive of the peduncle, show 
fifteen or more sporophylls in a vertical row (fig. 14). 
MATURE SPOROPHYLLS AND SPORANGIA 
The mature microsporophylls of Zamia floridana are short- 
stalked and broaden outwards from their insertion, the sterile tip 
being thick and hairy. The microsporangia are borne upon the 
abaxial surface, and are grouped upon either flank, with the median 
region of the sporophyll bare. The sporangia extend to the margin 
but not beyond, so that there is no appearance of a “peltate expan- 
sion” of the sterile tip. 
The microsporangia of Ceratozamia mexicana are borne upon 
obovate, cuneate sporophylls, whose sterile tips are produced into 
two horns spreading laterally. The sporangia cover the whole lower 
part of the sporophyll. The plates given by Warminc (7) show 
young stages of the sporophyll, when the sporangia are in two groups, 
one on either flank; but in the text he says that in further growth 
they become more numerous and spread toward the median region, 
so that at last this is covered. 
In Encephalartos villosus the sporophyll has a very short stalk 
or is sessile; the tip is sterile and produced into a blunt point. The 
sporangia in the central sporophylls of the strobili cover the surface, 
but at the apex the outline of the sporangium-bearing area is notched 
_ in the center, showing a tendency toward a two-grouped arrangement. 
Single strobili of E. Caffer and of E. Altensteinii have been examined, 
and in both species throughout the median region of the cone the 
sporangia cover the sporophylls; but the lower sporophylls on the 
cone and those at the tip show fewer sporangia, and these are grouped 
into two lateral areas. The transition between these two conditions 
