2C4 
MORPHOLOGY 
veins that branch dichotomously, except in certain forms with very 
narrow leaves. In some forms the leaves are short and obovate, sug- 
gesting those of Gink- 
goales. The structure of 
the leaves is like those 
of the cycads, with the 
very characteristic meso- 
phyll (see p. 193). In 
form, therefore, the leaves 
in general resemble those 
of the conifers ; but in 
structure they resemble 
those of the cycad line. 
Strobili. The strobili 
are small and monospo- 
rangiate, both kinds of 
strobili usually occurring 
on the same plant (monoe- 
cious), characters which 
belong to the conifers. 
They occur in clusters 
on lateral branches (fig. 
461), and both kinds are 
sheathed by bracts. 
Staminate. The stam- 
inate strobilus is made up 
of spirally arranged sterile 
bracts, among which the 
stamens occur, either soli- 
tary or grouped near the 
apex (fig. 462). Each 
stamen is a slender stalk 
bearing a terminal cluster 
of three to six erect spo- 
rangia with longitudinal 
dehiscence. It is only among the Cycadofilicales that such terminal 
and erect microsporangia are found (cupule type, see p. 184). 
Ovidate. The ovulate strobilus is made up of conspicuous over- 
lapping bracts, in whose axils short branches appear, each of which 
FIG. 461. Restoration of Dorycordaites, one of 
the Cordaitales, showing the branching habit, the 
simple, elongated, parallel-veined leaves, and the 
clusters of strobili borne on lateral branches. After 
GRAND 'EURY. 
