136 ('. I'. Wieland -Williamsonian Tribe. 



playing every phase of monoeciem, diooeism, and bisexuality, 

 coupled with a continuous series of sporophyll reductions, ster- 

 ilizations, and increasing flower output. 



The steins and leaves of this great series considered merely 

 as typical and cosmopolitan cycad vegetation (cf. Map, fig. 1), 

 of course held scant interest for the biologist; though now 

 that to initial knowledge of the sporophylls has been added a 

 complementary knowledge of the cycadofilicaleans, no one may 

 set boundaries to the harvest of new fact certain to be yielded 

 by the Cycadophyta year by year. 



But while enumerating these new fields for exploration and 

 reciting recent Williamsonia discoveries, it is of more than 

 merely retrospective interest to further show how truly rich 

 some of the earlier Williamsonia collections from the York- 

 shire coast really were. And this we may readily do by illus- 

 trating in their order a series of ovulate specimens originally 

 forming a portion of the celebrated James Yates collection, 

 but now transferred to the Yale Museum collections by the 

 Curators of the Paris Museum. This interesting illustrative 

 series, of historic as well as structural interest, forms a nearly 

 indispensable complement to the Yale collection of Cycade- 

 oideans which it had become a special aim to secure ; and as a 

 just equivalent there was turned over to the collections of the 

 Jardin des Plantes a unique quadruply branched trunk of 

 Cycadeoidea Marshiana of large size, — probably the only 

 distinctly branched specimen of its kind in any European 

 museum. In addition, I am enabled through the unfailing 

 courtesy of the French curators to present figures of several 

 other characteristic specimens of the Yates collection of much 

 interest as being the forms with Yuccites-like features (figures 

 2 and 11A) which reasonably explain the earlier variant views 

 of the Williamsonia habitus. But before turning to these 

 interesting specimens, we may briefly consider the stems and 

 then the foliage of Williamsonian types, progress in the study 

 of the group now fairly permitting this normal order. 



Trunks of Williamsonice. (Figures 2-4.) 



So far as critical details go knowledge of Williamsonian wood 

 types has not kept pace with that of either the foliage or 

 flowers, despite the fact that more or less imperfect casts and 

 imprints of various kinds of stems are of constant occurrence in 

 the cycad-yielding terranes. Williamson early noted slender 

 stems of cycadaceous character accompanying the Zamites 

 gigas fronds and fruits of the Yorkshire coast so persistently 

 as to justly lead him to the conclusion that these remains, 



