CHAP. III. PHLOX SU3ULATA. 



unattached portion being alone measured ; but this ratio can- 

 not be trusted, owing to the great variability of the stamens. 

 The mean diameter of eleven pollen-grains from long-styled 

 flowers, and of twelve from <ihe short-styled, was exactly the 

 same. It follows from these several statements, that the dif- 

 ference in length and state of surface of the stigmas in tin- 

 flowers is the sole reliable evidence that this species is hetero- 

 styled; for it would be rash to trust to the difference in tho 

 length of the pistils, seeing how variable they are. I should 

 have left the case altogether doubtful, had it not been for the 

 observations on the following species; and these leave little 

 doubt on my mind that the present plant is truly heterostyled. 

 Professor Gray informs me that in another species, (?. coronopi- 

 folia, belonging to the same section of the genus, he can see no 

 sign of dimorphism. 



A few flowers sent me from Kew had been somewhat injured, 

 so that I cannot say anything positively with respect to tho 

 position and relative length of the organs in the two forms. 

 But their stigmas differed almost exactly in the same manner as 

 in the last species ; the papillae on the long-styled stigma being 

 longer than those on the short-styled, in the ratio of 100 to 4_. 

 My son measured nine pollen-grains from the long-styled, anil 

 the same number from the short-styled form; and the in can 

 diameter of the former was to that of the latter as 100 to 81. 

 Considering this difference, as well as that between the stigmas 

 of the two forms, there can be no doubt that this species is 

 heterostyled- So probably is Oilia nudicaulis, which likewise 

 belongs to the Leptosiphon section of the genus, for I hear from 

 Professor Asa Gray that in some individuals the style is very 

 long, with the stigma more or less exserted, whilst in others it 

 is deeply included within the tube; the anthers being always 

 seated in the throat of the corolla. 



PHLOX SUBULATA (POLEMOHIAOE.E). 



Professor Asa Gray informs me that the greater number of 

 the species in this genus have a long pistil, with the stigma 

 more or less exserted ; whilst several other species, especially the 

 annuals, have a short pistil seated low down within tlie tube ol 

 the corolla. In all the species the anthers are arranged one 

 9 



