1907] SMITH—TRUNK AND MICROSPORANGIUM OF CYCADS 191 
ovulate strobilus was formed agreed in the details of development with 
those of the staminate strobilus, and like them the several strobili may 
mature the same year. This is not infrequent in Zamia floridana. 
The trunk of the cycads, and especially of Zamia, is capable of 
forming new tissue readily upon wounding, as CoULTER and CHRYSLER 
(22) have shown. Since there is this power of forming secondary 
meristem, it may be that some of the cases of lateral shoots, pro- 
duced upon the lower part of the trunk, are the results of wounding. 
Since other cycads are known to produce more than one strobilus 
upon the trunk in the same year, the manner of growth of the stem 
in these forms may be the same as in Zamia. The staminate cone 
mentioned by DEBary (10) had the same position as those of Zamia, 
with the vegetative point at the base of the cone, so that this case may 
be explained as a sympodium, and there may have been no stunting 
of the point as DeBary thought. In view of these facts it seems 
probable that in all the other genera the branching is sympodial, 
except in the case of the ovulate plants of Cycas. 
The successive pushing aside of the terminal strobili in Zamia 
(fig. 5) suggests comparison with Bennettitales, as described by Scott 
(17) and WIELAND (19), in which the strobili arise terminally on 
short, lateral branches, wedged in between the bases of the leaves. 
In the modern cycads, as illustrated by Zamia, the strobili finally 
occupy positions in the axils of the leaves, and the vegetative point 
crowns the stem at the end of the year’s production of strobili. 
II. Microsporophylls and microsporangia 
DEVELOPMENT OF SPOROPHYLLS 
The youngest staminate strobilus of Zamia floridana was obtained 
from material received from Miami, June 1, 1905. The leaves 
were removed from the crown of the plant and the small cone exposed, 
less than 1™™ in length (fig. 7). The leaves in a vegetative point 
arise as small protuberances from the extreme base of the meriste- 
matic apex and incline toward each other, covering the point of growth 
(fig.8). The strobilus, however, rises higher before showing any pro- 
tuberances, and when these appear they rise acropetally and project at 
right angles to the cone (jig. 9). In the strobilus shown in jig. ro the 
sporophylls are not much farther advanced than in fig. 7, but the 
strobilus has lengthened and there are more primordia of sporophylls. 
