382 Cooke and Schively on Observations on the 



rather small, spherical thin-walled cells, showing no inter- 

 cellular spaces. All of these cells are well filled with deeply- 

 stained protoplasm, and have a very large and dense nucleus 

 and nucleolus. Starch grains are present in considerable 

 quantity. 



This nectary may probably be regarded as the remaining 

 trace of the fifth stamen that should be present to preserve 

 agreement of number throughout the flower. The presence 

 of this nectary is also evidence that this plant was once a 

 typically insect-pollinated form. It is rather remarkable 

 that it should be so well developed in the cleistogamic flow- 

 ers of the present time, where it is entirely useless. This 

 persistence of the nectary, and also the production of the 

 primitive chasmogamic flowers, seem to indicate that para- 

 sitism in this plant must perhaps not have been of so very 

 ancient date. At any rate, modifications due to parasitism 

 are still occurring, and the plant is at present in a somewhat 

 transitional state. This is especially indicated by the pro- 

 duction or non-production of chasmogamic flowers, by the 

 variable development of roots and by the evolution of two 

 types of floral structure that are united by intermediate 

 stages. 



The style and stigma are identical structures in the two 

 flowers, except for differences in size. The style is elliptical 

 in section. Two vascular bundles traverse its length. These 

 are well developed, and show phloem cells, also numerous 

 spiral tracheje. Toward the stigma these elements loosen 

 and spread apart noticeably. Simple two-celled stomata 

 are numerous along the entire length of the style, but are 

 present in greatest number midway between the ends. 



The stigmatic surface has the aspect of a broad convex 

 cap set on the end of the style. It is thickly covered with 

 short, round swollen unicellular hairs. 



There is a marked horizontal division through the style. 

 In all cases there is evident a thinned-out, broken region 

 across the style midway between the two bundles. In the 



