aE 
1907] SMITH—TRUNK AND MICROSPORANGIUM OF CYCADS 193 
can be traced in a series of sporophylls, which show the outline of the 
sporangium-bearing area becoming notched in the middle region 
above and below, and the notches gradually deepening until finally 
the middle region becomes bare. This series also occurs in Dioon 
edule; and in the one cone of Macrozamia Miquelii examined it was 
shown by the sporophylls at the base; but those of the central part 
and tip were entirely covered with sporangia. 
The numbers of sporangia on a sporophyll range as follows: 
Cycas circinalis 700, Encephalartos Caffer 700, Macrozamia Miquelii 
600, Encephalartos villosus 500, Dioon edule 200, Zamia floridana 24. 
The sporangia on the outside of the sporophyll flank in Zamia 
floridana and Ceratozamia mexicana, also in Stangeria as recorded 
by LANG (16), are likely to have longer stalks than the sporangia on 
the central part, and are more rounded. In Ceratozamia they are so 
crowded that they become angular, often irregular in shape, and 
encroach upon one another (fig. 15); and, as in Stangeria, there are 
many hairs among the sporangia, arising from the sporophyll. In 
Zamia floridana and Encephalartos villosus there are no hairs in the 
region where the sporangia are borne. 
The sporangia are definitely grouped into sori, arising from a 
cushion of meristematic tissue elevated slightly above the sporophyll 
(fig. 16). Two to five sporangia occur in the sori of Ceratozamia, 
Stangeria (according to LANG), Macrozamia Miquelii, Encephalartos 
villosus, and E. Caffer; two to four in Cycas circinalis; and seldom 
more than two in Zamia floridana. Into this soral cushion there is 
an extension of the vascular system, as in the synangia of Marattiaceae. 
LANG (16) found the sporangia of Stangeria in every stage of 
development on the sporophyll, beginning at the center of each flank 
and extending toward the margin and middle region. He refers 
to WARMING’s (7) figures of Ceratozamia to show that in that form 
the sporangia on a sporophyll are of the same age; but WARMING’S 
text distinctly states that at first there are groups of twenty to thirty 
on each flank, and by further growth these spread so as to conceal 
the middle region. In my material of Ceratozamia, which was 
nearly all mature, the sporangia were about the same age; but a few 
on the edges and toward the center were a little younger. 
In Zamia and Ceratozamia there is strong suggestion of the syn- 
