INCREASE OF CYCADE.E BY BUDS. 499 
Mode of increase by Buds the same in recent 
and fossil Cycadece, 
The Cycas revoluta figured in PI. 58* pos- 
sesses a peculiar interest in relation to both our 
of vessels seem to partake of the laminated disposition of the 
woody circle within the trunk. 
An agreement is found also in the longitudinal sections of 
the Petioles of recent and fossil Cycadese. PI. 62, Fig 1, is 
the longitudinal section of part of the base of a Petiole of Zamia 
spiralis, magnified to twice the natural size. It is made up of 
cellular tissue, (f), interspersed with gum vessels, and with long 
bundles of vascular fibres, (c) proceeding from the trunk towards 
the leaf. On the lower integument, (b') is a dense coating of 
minute curling filaments of down or cotton, (a) which being re- 
peated on each scale, renders the congeries of scales surrounding 
the trunk, impervious to air and moisture. 
A similar disposition is seen in the longitudinal section of the 
fossil Petiole of Cycadites microphyllus represented at PI. 62, Fig. 
2, and magnified four times. At f, we have cellular tissue inter- 
spersed with gum vessels, h. Beneath c, are longitudinal bun- 
dles of vessels ; at b, is the integument ; at a, a most beautiful 
petrifaction of the curling filaments of down or cotton, proceed- 
ing from the surface of this integument. 
In the vascular bundles within the fossil Petioles, (c) Mr. 
Brown has recognized the presence of spiral, or scalariform vessels 
(Vasa scalariformia) such as are found in the Petioles of recent 
Cycadese ; he has also detected similar vessels, in the laminated 
circle within the trunk of the fossil Buds next to be described. 
The existence of vessels with discs peculiar to recent Cycadeae 
and Coniferee, such as have been described in speaking of fossil 
Coniferae, has not yet been ascertained. 
* This plant had been living many years, in Lord Grenville's 
conservatory at Dropmore. In the autumn of 1827, the external 
part of the scales was cut away to get rid of insects : in the fol- 
