50 RemarJcs on the Natural order Cycadea. 



in the structure of the seeds themselves, having the same integiH 

 ments, the same foramina in the ovula and micropyle in the mature 

 seed, with only such slight deviations in structure as might be ex- 

 pected from the peculiar economy of these orders. 



In a paper read before the "British Association for the Advance- 

 ment of Science," at the fourth meeting, held at Edinburgh in 1834,. 

 Mr. Brown has adduced a new point of analogy between Coniferae- 

 and Cycadeas, in the tendency which exists in both these orders ta 

 the production of a '^plurality of embryos'^ in the same nucleus. 

 Occasional examples of this plurality were not unknown in other 

 plants, but it was only in CycadcEe that any constancy in this partic- 

 ular had been observed. Mr. Brown's recent investigations, how- 

 ever, have demonstrated not only the general occurrence of this plu- 

 rality of embryos in many Pines, but also that a regular arrange- 

 ment of these embryos within the nucleus takes place with much- 

 uniformity in both these families.* 



A resemblance in inflorescence, fructification, and seed, are not 

 the only points of agreement between Cycadcce and Coniferae. The 

 simple cylindrical stem of the former, which resembles outwardly the 

 trunk of the Palms, (a monocotyledonou":! order,) has been shown 

 by M. Brongniart to be decidedly exogeiious in structure — probably 

 only growing in the form of a simple trunk, in consequence of the 

 non-development of the axillary buds. The leaves of both the Cy- 

 cas and the Fir tribes, as Prof. Lindley remarks, have the same par- 

 allel arrangement of veins, and both tribes exhibit a marked similar- 

 ity in the fewness of their spiral vessels. Cycadese and Coniferae 

 still farther agree in a character lately discovered, as unique as it is 

 important, and which alone would establish the fact of a strong affin- 

 ity existing between the two orders ; namely, the singular perfora- 

 tions in, or rather globules adherent to, the fibres of their wood, ta 

 which there exists nothing analogous in the structure of any other 

 tribe of p.lants.| 



* Since writing this paper, a work has reached lis, containing details of some re- 

 markable experiments and investigations, made by Corda, on the impregnation of 

 plants, conducted with that accuracy and minuteness so eminently characteristic 

 of the Germans, which tends to elucidate this hitherto obscure portion of structu- 

 ral botany. Corda's experiments were made upon plants of the order ConiferEe, 

 and the results are highly curious. Dr. Gray has lately read before the Lyceum 

 of Natural History of New York a translation of Corda's memoir, which will 

 probably soon be published. (See Vol. XXXI, p. 317. — Ed.) 



t So permanent is this characteristic, that geologists have recently through it 

 identified Coniferous wood, which has been imbedded in the coal strata for thou- 



