Mr. J. Morris on recetit and fossil Cycadea. 1 1 1 



The family is dioecious. The inflorescence consists of a stro- 

 biliform spike, from the under surface of the scales of which 

 the polleniferous thcca? proceed ; in Zamia these thecae are 

 separated into two distinct masses, Avhile in Encephalartos 

 and Cycas they form a confluent mass. 



The female inflorescence of Zamia and Eiicejihalartos is 

 similar to the male cones in form, having thick scales, each 

 bearing on the superior surface two naked ovula ; while in 

 Cycas the naked ovula are seated in depressions on the edges 

 of a frond but little altered from the ordinaiy structure. 



The foliation of this family consists of pinnate fronds, the 

 circinnate vernation of which, in a young state, has generally 

 been considered a character belonging to all the genera ; but 

 a series of observations on the development of the frond which 

 I have had an opportunity of making in several species of the 

 three existing genera, have led me to an opposite conclusion, 

 from which it is evident that even in Cycas itself the rachis is 

 constantly straight in the early state ; when however twelve 

 or more fronds rise together, the outer ones become incurved 

 at their extremities, apparently for the purpose of aflPording 

 some protection to the more delicate fronds within, which re- 

 main perfectly straight : the only parts to which the term cir- 

 cinnate can be strictly applied, are the young segments or 

 pinnae. In the evolution of the fronds the development pro- 

 ceeds from the base upwards, each pair of pinnae becoming- 

 unrolled as soon as that part of the rachis has attained its full 

 degree of extension and size. 



A correct figure of the young frond of C. circinalis is given 

 in Rheede's ' Hortus Malabaricus,' vol. iii. t. 15. f. 2, 3, 4 ; and 

 one of C. revoluta is figured in plate xi. fig. 4, 5, ' Mag. Nat. 

 Hist.' 1840, from a specimen obtained from Mr. Anderson, of 

 the Chelsea Botanic Garden. 



The prefoliation of Zamia and Encephalartos presents but 

 little difference from each other ; the young rachis is slightly 

 recurved at the apex, the two series of pinnae being regulai'ly 

 imbricated, and applied to, or in contact with, each other by 



great peculiarity of the Coniferoe, and wliicli distinguishes them as well from 

 Cycadeaa as from every other family^ is the remarkable uniformity of their 

 woody tissue, whicli consists of slender tubes, furnished on the sides parallel 

 to the medullary rays with one or more rows of circular or angular dots ; 

 but in Cycadere no such uniformity is observable, their tissue, as in other 

 phienogamous plants, consisting of two kinds of vessels, namely, of slender 

 transparent tubes, without dots or markings, and of dotted, reticulated and 

 spiral vessels, which are capable of being unrolled. The former are iden- 

 tical with the fibrous or woody tissue ; whilst the latter, which form a part of 

 each bundle, can only be compared to the strictly vascular tissue of other 

 plants." — (Proc. Linn. Soc. Feb. 4, 1840.) 



