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of fleshy or horny alt)umen ; the radicle next the apex of the seed, from which it hangs I)y 

 a long funiculus witli which it has an organic connexion Trees, with a simple cylin- 

 drical trunk, increasing by the development of a single terminal bud, and covered by the 

 scaly bases of the leaves ; the wood consisting of concentric circles, the cellular zones 

 between which are exceedingly loose. Leaves pinnated, not articulated, having a gyrate 

 vernation. 



Affinities. One.of the botanists who originally noticed the plants that 

 constitute this order referred them to the Fern tribe ; an opinion to which 

 Linnaeus, having first adopted the idea of Adamson that they were related 

 to Palms, finally acceded. He was followed by other botanists, until, after 

 some suggestions by Ventenat that the genera Cycas and Zamia ought to 

 form a particular tribe, the present order was finally characterised by the late 

 M. Richard in Persoon's Synopsis, in 1807, with the observation that it was 

 intermediate between Ferns and Palms. The opinion of their affinity to 

 Ferns seems to have been thus generally adopted in consequence of their 

 striking resemblance in the mode of developing their leaves; but the sup- 

 posed lelation to Palms, was suggested rather by a vague notion of some 

 general resemblance, as, for instance, in their cylindrical trunks, than by 

 any precise knowledge of the structure of Cycadese. It is only within a 

 few years that a more accurate knowledge of their structure has determined 

 the real nature of their affinities. In 1825, the publication of Mr. Brown's 

 remarks upon the ovulum, in which he demonstrated the similarity of con- 

 formation between the flowers of Cycadese and Coniferse, suggested new ideas 

 of the affinities of both tribes ; and the determination, in 1829, by M. Adolphe 

 Brongniart, of the exact resemblance between these two tribes in the struc- 

 ture of the vessels of their wood, while it decided the near relation of Coni- 

 fdrse and Cvcadege, confirmed the proximity of the former to Ferns,, and 

 shewed the inaccuracy of the ideas formerly held of a close resemblance 

 between the latter and Palms. As this is still a matter but ill understood in 

 general, it may be useful to make some further remarks upon the subject. 



It has been said that the dissimilarity between Cycadese and Coniferge is 

 such as to render it impossible to admit of their close approximation in any 

 natural arrangement; and that the affinity of Cycadeae being with Palms, 

 the former must necessarily be widely apart from Firs. These views of the 

 subject appear to have arisen either from an imperfect knowledge of the real 

 vegetation of-the stem of Cycadea>, or from a too superficial consideration of 

 such points as were really well known. The affinity of Cycadeae and Palms 

 does at first sight appear probable, in consequence of the large pinnated 

 leaves and simple cylindrical stems of both tribes ; but here I think the 

 resemblance stops. Cycadeae have a gvratc, Palms a convolute vernation ; 

 Cycadea^ are naked-seeded and bear their seeds on the margins of a con- 

 tracted leaf. Palms have the ordinary inflorescence of flowering plants ; 

 Cycadeae are dicotyledonous, Palms monocotyledonous ; and finally, the in- 

 ternal structure of the trunk of Cycadeae is essentially exogenous, as is 

 now perfectly well known : the affinity of Cycadeiu is therefore not with 

 Palms. With regard to the nature of the evidence by which their strict, 

 relation to the Pine tribe is to be established, it may be observed, that they 

 are both dicotyledonous in seed, both have naked ovula constructed in a 

 similar remarkable manner, and borne in both cases not upon a rachis, but 

 upon the margin or face of metamorphosed leaves ; that they have the 

 same peculiar form of inflorescence, the same kind of male flowers, the 

 same constant separation of sexes; that the arrangement of the veins of 

 their leaves is peculiar and identical ; that there is a like imperfect formation 

 of spiral vessels, a most important consideration ; and finally, that they both 

 agree in having the vessels of their wood apparently perforated with nume- 

 rous holes; a character, as far as is yet known, exclusively confined to these 



