360 Notes on Recent Literature. 
general arrangement the synangia are somewhat similar to those of 
recent Cycads, being, however, on the adaxial or upper side of the 
sporophyll. The synangia vary considerably in number and 
arrangement. In W. spectabilis they appear to be crowded together 
irregularly, and it is suggested that the sporophyll may be analogous 
to a pinnate frond bearing simple pinnae below and lobed ones nearer 
the apex. In W. whitbiensis, however, the synangia show a much 
more regular arrangement (cf. figure). They are attached to the 
A B 
Restoration of j flower of Williamsonia whitbiensis Nath. Nat. size. 
(A), Complete example. (B), A single sporophyll showing the form and attach¬ 
ment of the synangia, and the markings below them, which probably repre¬ 
sent rudimentary synangia. From fig. by Professor Nathorst. cf. Pal. Mitt., 
No. 9, p. 13, fig. 3. 
sporophyll by their short side and lie in two rows, one on either 
side of the axis. It is not possible to say whether the synangia 
were stalked or not, but if stalked the stalk was very short; in the 
lower part of the calyx (Becher) they were rudimentary. There 
seems to be little doubt that the much discussed “ carpellary disc ” 
of Williamson was a structure somewhat of this nature. The 
arrangement of synangia in some of these Yorkshire forms is there¬ 
fore similar to that seen in the Williamsonia from Mexico figured 
by Wieland, 1 where the synangia are borne in two rows on a 
reduced sporophyll which is fused to the calyx-like united bracts. 
But in the Yorkshire specimens, no sporophylls distinct from the 
cup-like bract segments can be distinguished. 
The male “flower” of Williamsonia thus presents a consi¬ 
derable difference from the microsporophylls of the Bennettitean 
strobilus, the synangia being borne on the surface of a flattened 
entire calyx-like structure and not on a highly-divided reduced frond¬ 
like structure. 
The female strobilus of Williamsonia is, however, almost 
identical with the corresponding structure in the genus Bennettites. 
The ovules are borne on stalks on a swollen receptacle among 
numerous peltate interseminal scales. The external surface of the 
mature strobilus is quite characteristic, being divided up into the 
1 Wieland. The Williamsonias of the Mixteca alta., Bot. Gaz., p. 427, 
1909. 
