rr 



Chap. III. RUBIACKZE. 133 



thers are larger, and the pollen-grains, when distended 

 with water, are to those from the long-styled form as 100 

 to 72 in diameter. 



Selected capsules from some long-styled plants growin_ 

 in the Botanic Gardens at Cambridge, U. S., near where 

 • plants of the other form grew, contained on an average 

 13 seeds; but these plants must have been subjected to un- 

 favourable conditions, for some long-styled plants in a 

 state of nature yielded an average of 21.5 seeds per cap- 

 sule. Some short-styled plants, which had been planted by 

 themselves in the Botanic Gardens, where it was not likely 

 that they would have been visited by insects that had pre- 

 viously visited long-styled plants, produced capsules, eleven 

 of which were wholly sterile, but one contained 4, and an- 

 other 8 seeds. So that the short-styled form seems to be 

 very sterile with its own pollen. Professor Asa Gray in- 

 forms me that the other North American species of this 

 genus are likewise heterostyled. 



Oldenlandia [sp.?] (Rubiace^e). 



Mr. J. Scott sent me from India dried flowers of a 

 heterostyled species of this genus, which is closely allied to 

 the last. The pistil in the long-styled flowers is longer by 

 about a quarter of its length, and the stamens shorter in 

 about the some proportion, than the corresponding organs 

 in the short-styled flowers. In the latter the anthers are 

 longer, and the divergent stigmas decidedly longer and 

 apparently thinner than in the long-styled form. Owing 

 to the state of the specimens, I could not decide whether 

 the stigmatic papillae were longer in the one form than in 

 the other. The pollen-grains, distended with water, from 

 the short-styled flowers were to those from the long-styled 

 as 100 to 78 in diameter, as deduced from the mean of 

 ten measurements of each kind. 



Hedyotis [sp.?] (Rubiace,e). 



Fritz Miiller sent me from St. Catharina, in Brazil, 

 dried flowers of a small delicate species, which grows on 

 wet sand near the edges of fresh-water pools. In the long- 

 styled form the stigma projects above the corolla, and 

 stands on a level with the projecting anthers of the short- 



