64 ON THE SEXUAL ORGANS OF THE CYCADACEE. 
a thorough revision, be found untenable, the characters relied on being 
either inconstant, or at most of merely sectional value, and the so-called 
genera being linked with each other by all kinds of gradations. Par- 
latore, who is by no means indisposed to recognize genera based on 
comparatively slight characters, provided these are constant, writing of 
those employed for the dismemberment of Scirpus, well observes,— 
* Genere immeritamente diviso in molti, fondati sopra caratteri falsi 
della presenza o mancanza delle sete del perigonio, dello stilo bifido o 
trifido, dell’ achenio triangolare o schiacciato, caratteri tutti variabili 
in questa famiglia, non solo nelle specie di uno stesso genere, ma an- 
cora negl' individui di una stessa specie, e fino nelle spighette di uno 
stesso individuo.” 
ON THE SEXUAL ORGANS OF THE CYCADACEA. 
By F. A. W. HU 
aer by W. THISELTON-DYER, Esq., B.A., the author’s French edi- 
on of the paper published in the ges [Diener t. iii. 1868.) 
In 1845, when I published some researches on the ovules, em- 
bryos, and male organs of the Cycadacee (Ann. des Sciences Nat. 
3me série, t. ii. et iv.), Gottsche published in the * Botanische 
Zeitung’ an important investigation of the same subject. The results 
of these wholly independent researches were, in many points, identical ; 
but Gottsche had taken a more comprehensive point of view by in- 
cluding the Conifer as well. At that time I had already completely 
abandoned the morphological views which I had previously published 
(* Monographia Cycadearum °) on the axial nature of leaves, as well as 
Richard's theory of the ovule. Robert Brown, by his investigations of 
the genus Pinus (* On the Plurality and Development of the Embryos 
in the Seed of the Conifere,” Annals of Nat. Hist., May, 1844), had 
ensured still more support for his theory of gymnospermous ovules 
first stated in 1826 (Appendix to Captain King's * Voyage ’).* 
It is well known how much the labours of Mirbel, Spach, Schleiden, 
* Previously read at the British Association nk at Edinburgh. Robe 
Brown afterwards added a note, to the effect that the ‘credit of the first idea m 
this theory does not belong to Mirbel; and x states that Aubert du Petit- 
Thouars had already noticed various points in the structure of the ovules of 
ded. 
Cycas, without ueing from them the notion of gymnospermous ovules. 
(Histoire des Vezet, des Iles d'Afrique.) a 4 
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