196 ON THE ASCLEPIABE^. 



a character at once obvious and important, and which while 

 it preserves the natural series unbroken, has the additional 

 advantage of dividing the order into two nearly equal parts. 

 To one of these which includes the genus Apocynum, the 

 name of Apocinese will of course remain. 



The consideration of the other, which from one of its 

 most remarkable genera I propose naming AsclepiadejE, 

 forms the chief subject of the following essay'; but the more 

 completely to illustrate it, I have subjoined new, and I 

 trust amended characters of the genera of the most nearly 

 related section of the Apocinese strictly so called. The 

 u] singular structure of the stamina in the Asclepiadese has 

 attracted the attention of botanists since the days of 

 Tournefort : it is therefore not a little remarkable, that two 

 opposite opinions should still be held even respecting the 

 origin of these parts, and that between these opinions bota- 

 nists should be almost equally divided. 



In a paper which was some time ago read to the Linnean 

 Society of London,-^ I had occasion, in inculcating the neces- 

 sity of examining the parts of the flower before expansion, 

 to advert to this tribe of plants ; and I there entered at 

 some length, both into the opinions generally received re- 

 specting their male organs, and also into that which I had 

 deduced from an examination of these parts before the 

 opening of the corolla : and being unwilhng to repeat now, 

 what I then stated, I shall content myself with referring to 

 the figures and descriptions published by Jacquin in the 

 first volume of his " Miscellanea Austriaca," which give a 

 correct idea of the state of the organs after expansion ; and 

 only add the observations I have made on one species of 

 the family, the Asdepias Syriaca, in the earlier stages of 

 the flower. 



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 stigma were 

 absolutely invisible ; the furrows of its angles were ex- 



' \_Ante., pp. 6—8.] 



