HOMOLOGIES OF THE 



Chai'. VII I. 



SO many groups of spiral vessels, in every case traced 

 down to one of the six large ovarian gron{)S. They 

 alternate in five whorls, as represented ; but I have not 

 attempted to give the actual distances at which they 

 stand apart. In order to guide the eye, the three 

 central groups running to the three pistils are con- 

 nected by a triangle. 



Fig. 36. 

 Upper or posterior sepal. 



Upper 

 petal. 



Lower 

 sepal. 



Labelluni. 



Section of the Flower of an Orchio. 



The little circles show the position of the spiral vessels. 



SS. Stigmas; S,, stigma modified a, a,- Kudimentary anthers of the 



into the rostellum. inner whorl (fertile in Cv])vi- 



A,. Fertile anther of the outer pedium), generally forming 



whorl; A^ A3, anthers of the the clinandrum ; tij, third 



same whorl combined with ■ anther of the same whorl, 



the lower petal, forming the , when present, forming the 



labellum. | front of the column. 



Five groups of vessels run into the three sepals 

 Liogether with the two upper petals ; three enter the 



