American Fossil Cycads. 245 
be present, no such have actually been determined.” In th e mature 
ovulate cones only these withered disks occur, indicating a pro- 
tandrous condition of the cone. The dicotyledonous embryos, 
already well-known in the seeds of the European specimens of 
these plants, also occur in the American species; the discovery of 
pre-embryonal stages exhibiting “ a partial agreement with Gingko 
in which there is no intervention of suspensors in the formation of 
the embryo from the homogeneous mass of large-celled tissue 
constituting the pro-embryo or protocorm ” is another of the weighty 
results of our author’s work. “And,” he adds, “ there is probably 
at hand material which, when once fully elaborated, will disclose 
the main outlines of embryogeny in the Cycadeoideae.” 
But the climax of interest is reached in Chapter VII., where, 
by dint of ingenious analysis of highly complex conditions of 
structure and of an equally ingenious synthesis shewn in the striking 
and beautiful restoration-figures, the author describes for us the 
male reproductive organs as they occur in these remarkable pro- 
tandrous, bract-ensheathed “ flowers.” These silicified flowers only 
occur in the bud-condition. “The ovulate cone is elongate, and its 
ovules are young and borne on very short pedicels.” “ The stami- 
nate disk is formed by a series of from ten (in C. Jenneyana) to 
eighteen or twenty (in C. dacotensis ) once-pinnate fronds with a 
strong basal adnation of their petioles continuing nearly to the 
summit of the central cone.” “Each frond bears about twenty 
pinnules closely set with two sub-laterally attached rows of distichous 
and sessile synangia, and is of partially circinnate prefoliation, being 
once inflexed, so that the upper third of its length lies with the 
ventral surface of the rachis appressed to the central cone, the 
fertile pinnules being folded back in pairs between the ascending 
and descending limb of the rachis. And since the pinnules follow 
in close order, all this intervening space is densely packed with 
synangia, the sporangial loculi of which are often filled with pollen.” 
It is pointed out that “ the compact bud-like form and fairly mature 
stage of growth in a protected position were very important factors 
in preservation.” The synthesis of restored structure has been 
chiefly attained by means of a remarkable series of transverse 
sections extending from the level of the peduncle upwards, text-figures 
of which are given. 
Such nightmare inexplicabilities as the “ pyriform axis,” “ car- 
pellary disk,” &c., of Williamson’s “ Zamia gigas ,” described by 
him in the darker period of palasobotanic research, appear, in the 
