DR. HOOKER ON WELWITSCHIA. 157 



between the gyinnospermous and angiospermous Dicotyledons ; 

 and that the ideal race consisted of hermaphrodite plants, in 

 which the office of the stigma of the carpellary leaf was per- 

 formed by a stigmatic dilatation of the ovular coat itself." 



This assumes that the gymnospermous theory established 

 by Brown is correct (whatever be the nature of the cone- 

 scales, rameal or carpellary, simple or compound), and ap- 

 plicable to the Gnetaceous as well as to the Coniferous type. 

 This view, lately much questioned, Dr. Hooker maintains, 

 and enforces, as respects Gnetacem^ by very convincing and 

 in part wholly original arguments, drawn from his own re- 

 searches upon the present plant and its allies. We refer to 

 pp. 28 to 31, which we could not readily condense, and have 

 not room to copy. The same is to be said in regard to the 

 resemblances or analogies in gynsecial structure between 

 Gnetaceai and LorantliacecG^ etc., — a subject upon which we 

 await expectantly Professor Oliver's investigations. More- 

 over, as Dr. Hooker remarks upon another page, the decisive 

 or final comparative view of the structures in question cannot 

 be had until the homology of the ovule itself is settled. In 

 cases where the flower is so simplified that the nucleus of 

 an ovule directly terminates the floriferous axis, and is sur- 

 rounded by few and simple, or peculiarly specialized, invest- 

 ments, the discrimination of these must be difficult enough, 

 and must ultimately depend upon the theory adopted as to 

 the nature of the ovular coats. If these be regarded as foliar 

 (as a rigid application of adopted morphological principles 

 will require), then a complete transition from gymnospermy 

 to angiospermy is probable, and may be expected to be de- 

 monstrable. 



The fertilization and embryology of AVelwitsehia have been 

 wonderfully worked out, considering the materials, by Dr. 

 Hooker, and the two most elaborate and valuable plates of 

 the memoir are filled with the details. Suffice it to say, that 

 it appears that the pollen must be brought by insects to the 

 ovule of the female flowers, at an early period, before the 

 nucleus is covered by the ovular coat or by the periantli, and 

 before the former has produced its styliform apex, down 



