259 
Slopes . — Roots in Bennettites . 
running in various directions among the breaking tissues of the leaf-bases, 
can scarcely belong to the main system of the trunk. It is possible that the 
old leaf-bases of some Bennettites gave rise to adventitious buds, and, if so, 
that these rootlets belonged to them. Indeed, there seems to be a certain 
amount of evidence accumulating in favour of the view that detachable 
vegetative buds may have occurred in this fossil group. In the living genus 
Cycas, which is vegetatively so comparable in some ways with Bennettites , 
adventitious buds which ultimately led to ‘ branches ’ were described , 1 which 
had roots running irregularly in and out of the leaf-bases of the trunk. It 
is true that I did not observe in the living Cycads any rootlets so slender, or 
any provided with root-hairs like the fossil, but my examination of the 
living Cycads was not exhaustive, nor are these points of fundamental 
distinction. Wieland 2 has well illustrated the queer irregular branching of 
some of the fossil trunks, which is irresistibly reminiscent of those of the 
Japanese living Cycas. It is therefore extremely probable that some 
adventitious budding took place in the fossil genus. 
Though it remains to some extent still a supposition, I conclude that 
the adventitious rootlets here described belonged to adventitious buds 
arising from the old leaf-bases of B. Saxbyanus itself. 
I must register my appreciation of Dr. Smith Woodward’s kindness in 
placing at my disposal the slides and other treasures of the geological 
collections of the British Museum (Natural History) to facilitate my work 
on the Bennettitales, of which this paper forms a small part. 
1 Stopes, Marie C., 1910 : Adventitious Budding and Branching in Cycas. New Phytologist, 
vol. 9, pp. 235-41, Text-figs. 8-14. 
2 Wieland, G. R., 1906 : American Fossil Cycads, pp. 296, PI. L. Carnegie Inst. Publ., No. 34. 
EXPLANATION OF PLATE XIV. 
Illustrating Dr. Stopes’s paper on Roots in Bennettites. 
Fig. 1. Weft of root-hairs running in space between the leaf-base tissues. b, root-hair base 
attached to rootlet. 
Fig. 2. Free rootlets with root-hairs attached. 
Fig. 3. Longitudinal section of rootlet showing cortical and vascular tissues. 
Fig. 4. Rootlet running in the tissue cells of the leaf-base: in this position the rootlets are 
without root-hairs. 
