1907] SMITH—TRUNK AND MICROSPORANGIUM OF CYCADS 189 
tion, although he says that it must be proved in either case by stages 
from young cones. 
BRAUN (5) definitely suggests sympodial branching, regarding the 
staminate and ovulate strobili as terminal, and quoting KaRsTEN 
as given above. ENGLER and PRANTL (14) in turn quote BRAUN. 
WARMING (7), in his investigation of Ceratozamia, decides that the 
staminate strobilus is terminal, and in an excellent drawing of a trans- 
verse section through leaves and strobilus shows the bud appearing in 
the axil of one of the leaves and continuing the principal sympo- 
dium. The peduncle of the strobilus is indicated between two leaves. 
SAcHS (g) and GorBEL (11) state in effect that if the strobilus 
is single it stands as a terminus of the stem; but if there are two or 
more strobili, as in Zamia muricata and Macrozamia spiralis, they 
may be the result of the forking of the stem. 
CouLTER and CHAMBERLAIN (19) state that the staminate strobilus 
in Cycas, at least, is terminal; but that in the other genera its true 
position, although apparently terminal, remains in doubt. Strobili 
may occur singly or several together, and in the latter case, at least, 
are considered lateral. 
WorSDELL (25) follows the theory of the sympodium in part, 
stating that each strobilus is developed as a continuation of the main 
axis, and that growth in length is continued by means of a lateral 
vegetative shoot immediately below the strobilus, the latter being 
pushed to one side. He also suggests monopodial branching, where, 
‘as is frequently the case, short lateral shoots are developed at inter- 
vals upon the main axis.” 
This historical sketch shows that the branching of the cycadean 
trunk has been regarded bf various writers as dichotomous, as mono- 
podial, and as sympodial. 
In preparing the material so that the strobili could be severed 
from the stem for killing, the petioles of old leaves and the scale 
leaves had to be removed carefully from the top of the stem; for 
often in the younger stages the strobilus is almost concealed by the 
growing tissue around it, only the tip projecting above the firm tissue 
of the stem. This tip is completely covered by scale leaves, 'so that 
often the strobili reach the stage in fig. 74 before the tip emerges 
from the scale leaves. In many cases more than one strobilus was 
