112 Mr. J. Morris on recent and fossil Cycadea. 



their anterior surface. See E. horrida, pi. 11. f. 2. and Z. pyg- 

 mma and pumila, f. 1, 3. ' Mag. Nat. Hist.' April 1840. I had 

 made these observations on the prefoliation of this family, 

 when examining the extensive collection of species belonging 

 to the Messrs. Loddiges of Hackney (who kindly furnished 

 me with any specimens I required), previously to my atten- 

 tion being called by Prof. D. Don to some remarks by M. 

 Miquel on this subject ; and as they appear to differ from my 

 own, owing probably to the period at which the young frond 

 was examined in both instances, 1 shall insert an abstract 

 from M. Miquel's memoir, with a view of calling the atten- 

 tion of botanists to a further investigation of this subject. 



" In Encephalartos affinis, Lehman, a bud is composed of 

 young leaves foreshortened (raccourcis), the tops of which 

 converge at the summit ; and the pinnae on each side of the 

 rachis, in consequence of this foreshortening, are imbricated 

 and placed in contact one with another by the anterior sur- 

 face. The same curious fact is observable in E. Altensteinii 

 and horridus, Lehm. In species of this genus the terminal 

 bud generally develops itself at an interval of two or even 

 more years ; and in young plants or the lateral buds of large 

 stems it is often only developed by a single frond, or by a very 

 limited number at one time. The increase of the young fronds 

 is produced by the extension of the rachis and pinna. E, spi- 

 ralis, Lehm., presents exactly the same character. In the 

 Zamia, Lehm., the fronds are developed in a totally different 

 manner. In Z. pumila and media, in the bud, the young rachis 

 is rolled into the form of a crozier ; but the two series of pinnae 

 are imbricated on each side, and are joined one with another 

 in such a manner that their tops are directed downwards, oc- 

 casioned by the circinnate disposition of the rachis. In the 

 young fronds of Cycas circinalis and revoluta, Thun., the 

 rachis as well as the pinna are rolled in the form of a crozier ; 

 each having a peculiar line or axis of circinnation, the same as 

 in Ferns*.'' 



The remains of fronds supposed to belong to this family 

 being rather numerous in a fossil state, and as the structural 

 characters vary in the three recent genera, I shall give a slight 

 description of the pinnae and their mode of attachment, il- 

 lustrated by a woodcut of each type. 



Cycas. — Pinnae linear, lanceolate, entire acute, having a single thick 

 midrib t attached to the rachis by their whole base, the lower 

 part of which is slightly decurrent. 



* Bulletin des Sciences Physiques de Neerlande, t. i. p. 129. 

 t In carefully examining the cellular substance of the pinnse, small veins 

 may be seen passing between the midrib and the margin. 



