Fecundation in OrchidecB and Asclepiadea. 737 



closed in the cells of the antherse ; this happening 

 in A . phytolaccoides in that particular kind of decay 

 mentioned in (p. 729 of ) the text. 



Tab. 36. 



Fig, 1. Two Pollen masses of Asclepias purpurascens with pro- 

 truded tubes ; the only instance met with in which 

 both cords are introduced into the same style. 



2. A grain of pollen, of the same species, with a portion 



of its tube ; the unusual form probably caused by the 

 pressure of other grains and their tubes. 



3. A grain of pollen of Asclepias purpurascens containing 



numerous minute granules and two larger drops or 

 globules of an oily fluid. 



4. 5, & 6. Various combinations of pollen masses of Ascle- 



pias purpurascens. In these it is supposed that the 

 insect having removed and applied to the stigma some 

 of the masses, has extracted, by means of the arms 

 still adhering to it, other masses with their glands 

 and arms. 



A combination of the same kind, different from and 

 more remarkable than any of these, but perhaps not 

 very accurately represented, is given, in his Micro- 

 scop. Entdeck., tab. 36. fig. 8, by Gleichen, who ap- 

 pears (op. cit. p. 81.) to have also met with other 

 combinations, without suspecting in any case the real 

 cause of such apparently anomalous structures. 

 7. A flower-bud of Asclepias curassavica in the earliest 

 stage in which I was able to distinguish its parts ; the 

 unopened corolla in its place with one of the sepala, 

 the other four being exhibited separately : — highly 

 magnified. 



5 B 2 Fig. 8. 



