300 MR W. GRIFFITH ON THE GENUS GNETUM. 



This paper owes its existence to Dr. LincUey, who with his usual kindness pointed out to 

 me this, among several other genera, as an interesting subject for study. In glancing over 

 the history of this genus, we find that very little additional information had been acquired 

 upon its structure from the period of its original publication by Linnteus, from whose 

 character all the subsequent ones have been more or less derived, imtil the appearance of 

 Dr. Browa's Memoir relative to the character and description of Kiiigia appended to 

 King's Voyage*. Previous to the appearance of this important publication, all botanists 

 who had noticed this genus had ascriljed to the female flower the ordinary structure. It 

 will hereafter be seen that all those who have formed this opinion of the structure of 

 Gnetum have examined the female flowers at a rather late period. 



Dr. Brown, in the Memoir above referred to, p. 23, gives it as his opinion, that in 

 Ci/cadece, Coniferce, Ephedra, and Gnetum., the ovarium is either altogether wanting, or 

 so imperfectly formed that the ovulum itself becomes directly exposed to the action of the 

 pollen. He further states that " the similarity of the female flower in Cycadece and 

 Conifer (B to the ovulum of other phsenogamous plants, as I have described it, is indeed 

 sufficiently obvious to render the opinion here advanced not altogether improbable ; but 

 the proof of its correctness must chiefly rest on a resemblance, in every essential point, 

 being established between the inner body in the supposed female flower in these tribes, 

 and the nucleus of the ovulum in ordinary structures, not only in the early stage, but 

 also in the whole series of changes consequent to fecundation. Now, as far as I have yet 

 examined, there is nearly a complete agreement in all these respects." 



After repeated examinations of Cycas, Gnetum, and Agathis, in their growing states, it 

 may perhaps not be considered presumptuous in me to add my feeble testimony to the 

 extreme accuracy of this statement of Dr. Brown t- 



Professor Lindley, in liis valuable ' Introduction to the Natural System of Botany,' 

 while he admits to the fullest extent Dr. Brown's notions on Cycadece and Coniferce, 

 appears to entertain the old opinion as to the structure of Gnetum ; and here it is again 

 evident that this truly philosophical botanist has only examined somewhat advanced 

 female flowers. I find, however, that in his remarks on Garrya (Bot. Register, vol. vii. 

 new series, t. 1686), this author has adopted the opinion of Dr. Brown, and speaks of 

 Gnetacea, a naked-seeded order. 



Having thus briefly alluded to the opinions entertained on the structure of this 

 singular genus, I shall now proceed to the consideration of the structure and develop- 

 ment of the female flower, which consists of a single naked ovulum. 



At a period long before the exsertion of the anthers, the ovula, which lie upon the male 

 flowers, are generally of an oljlong form, and consist of a central cellular solid body, 

 enclosed in two envelopes. The outermost of these is fibro-cellular, and divided longitudi- 

 nally on the upper face, or that nearest the axis, the fissure extending nearly to the base 

 of the ovulum t. The inner or second envelope is cellular, and is divided irregularly 



* Of this Memoir I have seen only an 8vo copy, in the possession of Dr. Wallich. 



t At the same time, Dr. Brown's observations refer only to a period subsequent to the appearance of the additional 

 membrane. (See Kingia, p. 25.) 



t This division is perhaps similar to that which Dr. Brown states to take place in Daciyr/iiim. 



