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liar character of their reproductive apparatus ; but this is of so unusual a kind 

 in Asclepiadeae, that it justifies a deviation from the general rule, that orders 

 cannot be established upon solitary characters. In Apocyneae the stamens are 

 distinct, the pollen powdery (that is to say, in the ordinary state), the stigma 

 capitate and thickened, but not particularly dilated, and all these parts distinct 

 the one from the other. But in Asclepiadese the whole of the reproductive ap- 

 paratus is consolidated into a single body, the centre of which is occupied by a 

 broad disk-like stigma, and the grains of pollen cohere in the shape of waxy 

 bodies attached finally to the 5 corners of this stigma, to which they adhere by 

 the intervention of peculiar glands. For a long time this structure was mis- 

 understood ; but Mr. Brown, in a dissertation in the Transactions of the Wer- 

 nerian Society, placed its true nature beyond doubt. I subjoin the explanation 

 given by this celebrated botanist, who thus describes the flower of Asclepias 

 syriaca : 



"The flower-bud of this plant I first examined, while the unexpanded 

 corolla was yet green and considerably shorter than the calyx. At this period 

 the gland-like bodies which afterwards occupy the angles of the stamen were 

 absolutely invisible ; the furrows of its angles were extremely slight, and, like 

 the body of the stigma, green ; the antherae, however, were distinctly formed, 

 easily separable from the stigma, and their cells, which were absolutely shut, 

 were filled with a turbid fluid, the parts of which did not so cohere as to sepa- 

 rate in a mass ; of the cuculli, which in the expanded flower are so remarka- 

 ble, and constitute the essential character of the genus, there was no ap- 

 pearance. 



"In the next stage submitted to examination, where the corolla nearly 

 equalled the calyx in length, the gland-like bodies of the stigma were become 

 visible, and consisted of 2 nearly filiform, fight brown, parallel, contiguous, and 

 membranaceous substances, secreted by the sides of the furrow, which was 

 now somewhat deeper. Instead of the filiform processes, a gelatinous matter 

 occupied an obliquely descending depression proceeding from towards the base 

 of each side of the angular furrow. 



" In a somewhat more advanced stage, the membranes which afterwards 

 become glands of the stigma were found to be linear, closely approximated, 

 and to adhere at their upper extremity. At the same time the gelatinous 

 substance in the oblique depression had acquired a nearly membranaceous 

 texture and a light brown colour ; and on separating the gland from its fur- 

 row, which was then practicable, this membrane followed it. At this period, 

 too, the contents of each cell of the anthera had acquired a certain degree 

 of solidity, a determinate form, and were separable from the cell in one mass ; 

 the cuculli were also observable, but still very small and green, nearly scutelli- 

 form, having a central papilla, the rudiment of the future horn-like process. 

 Immediately previous to the bursting of the cells of the antherae, which takes 

 place a little before the expansion of the corolla, the cuculli are completely 

 formed, and between each, a pair of minute, light green, fleshy teeth are 

 observable, the single teeth of each pair being divided from each other by the 

 descending alse of the antherae. The glands of the stigma have acquired a 

 form between elliptical and rhomboidal, a cartilaginous texture, and a brown- 

 ish black colour ; they are easily separable from the secreting furrow, and on 

 their under surface there is no appearance of a suture, or any indication of their 

 having originally consisted of two distinct parts : along with them separate 

 also the descending processes, which are compressed, membranous, and light 

 brown ; their extremity, which is still unconnected, being more gelatinous, 

 but not perceptibly thickened. The pollen has acquired the yellow colour, and 

 the degree of consistence which it afterwards retains. On the bursting of the 

 cells, the gelatinous extremity of each descending process becomes firmly 



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