1909] 



HILL— POLLINATION IN LIN ARIA 



459 



4 a cleistogene corolla enlarged ten diameters, that of fig. 4 dis- 

 played, the division being made between the two lobes of the upper 

 lip. The style and stigma, if rep- 

 resented, would be between the 

 two pairs of stamens as in the 

 ordinary flowers, the stigma in this 

 case closely pressed by the anthers 

 when the parts are in place. The 

 four stamens are apt to be present, 

 and slightly didynamous. Some- 

 times a small protuberance at the 

 base of the tube represents the 



spur 



In the smaller 



chasmoga- 



mous forms, this may be reduced to 

 a short sack or tooth, and usually 

 decreases in size as the other parts 

 diminish. But in some cases it 

 remains relatively longer in compari- 

 son with the lessened tube and limb. 

 I found no case of a cleistogene 



without a corolla. But as in other cases of cleistogamy it is'easy 

 to imagine the flowers represented by the calyx and the essential 

 organs of fructification. 



Figs. 1-4. — Linaria canadensis. 

 Fig. 1, petaliferous flower X5; figfe 

 cleistogene flower X 5 ; fig- 3, corolla of 

 cleistogene flower Xio; fig. 4/,. the 

 same, displayed, X 10. 



form 



have been noted by others. 



1 



Hills, mentions a L. canadensis collected at muster as uch 

 and depauperate, apparently with cleistogamous flowers. The 

 same has also been collected in Nebraska." 8 The month given for 

 Rydberg's collection is August. J. R. Webster records cases 

 observed by him at Milton, Mass., August, 1898. The plants were 

 again noticed the next year, being " examined almost daily from April 

 to October, and were seen to produce flowers abundantly which were 

 all cleistogamous." They were observed by him in other localities, 

 in which were also racemes which bore in addition fully developed 

 flowers.' As the plants at Milton are said to reach the height of 



8 Rydberg, P. A., Contrib. U. S. Nat. Herb. 3:517- 1896. 



• Webster, J. R., Cleistogamy in Linaria canadensis. Rhodora 2:168. 1900. 



