38 



root stocks. There can be no doubt that it is established here for 

 this is the second year that I have seen it and I could collect a 

 waggon load of it if necessary." 



It is quite likely that the material was sterile, as noted by the 

 collector, and that it depended on vegetative reproduction for 

 survival. Knowing nothing of the cytology of this particular group 

 of plants, one can do no more than speculate on its origin. How- 

 ever, it is safe to assume that the variety of characters in which 

 it differed from the normal form was not due to a single-gene 

 mutation, but involved a series of more drastic changes — none 

 of which was lethal to a plant able to propagate itself vegetatively, 

 as did this plant, forming a series of clones. 



Plate I 



Figures l-9b. Linaria vulgaris Hill 



Figures l-8c. Collected by Estil K. Handley, Mount Vernon, New York, 

 July, 1940. 



1. The single plant showing the various flower types. 



2a. External view of a flower bearing two small lateral spurs ; 2b, its 

 floral diagram indicating the presence of four functional stamens and one 

 vestigial stamen, as shown in 2c, the details of the reproductive organs. 



3a-b. External view and floral diagram of a flower similar to the above, 

 but with the fifth stamen somewhat more developed and bearing two pollen 

 sacs. The details of the reproductive organs of this flower are shown (in 3c) 

 enlarged. 



4a-e. The completely peloric flower. 4a, external view; 4b, its floral 

 diagram, the five spurs, five stamens and tricarpelled ovary may be noted; 

 4c, median section ; 4d, external view of the apex of the corolla ; 4e, median 

 section showing its refolded lip. 



5. Flower with bifurcate spur. 



6a-b. Flower with two well developed spurs and one small spur. A super- 

 numerary stamen was present between the larger spurs but the "fifth" 

 (adaxial) stamen was represented only by a tab of sterile tissue, much as in 

 Figure 2c. 



7a-b. A flower essentially similar to the preceding, but differing in having 

 the floral pattern reversed; also the "fifth" stamen bore a two-celled anther, 

 much as in Figure 3c. 



8a-c. Face and lateral views, and diagram of a flower with three spurs 

 and six stamens ; the "fifth" stamen was fully developed and the super- 

 numerary stamen was attached to the receptacle opposite the median spur. 

 Here the flower was assuming a balanced symmetry. 



9a-b. A specimen from the Torrey Herbarium (locality and collector 

 unknown but probably by John Torrey in the vicinity of New York City). 

 Here, two spurs had been developed; also, the apex of the corolla was 

 approaching the form of that assumed in complete peloria. 



