THE AMERICAN NATURALIST [ Vol. XL V 



out, the petals of 0. grand iff ora are also characteristic- 

 ally narrower and more cuneiform than in 0. La mar chi- 

 min, though this is not always the case. 



In a number of other flower characters 0. Larnarckiana 

 is more in agreement with 0. biennis, and contrasted with 

 0. grandiflora. Both the first-named species have quad- 

 rangular buds with a prominent median ridge on each 

 sepal, while in 0. grandiflora the buds are rounded and 

 the median ridge much less prominent. Also these two 

 species agree in bearing on the sepals, hypanthium and 

 ovary ;l conspicuous long, pointed type of trichome aris- 

 ing each from a papilla and giving the bud a rather 

 strongly pubescent appearance; while this type of hair 

 is, in my experience, always absent from the buds of 0. 

 grandiflora, which therefore have a glabrous appearance, 

 although a small inconspicuous type of hair is often 

 present, as is the case always in the other two species. 

 0. biennis and 0. Larnarckiana also agree in having 

 rather thick sepals and rather stout sepal tips, while in 

 O. grandiflora the sepals are thinner and more delicate, 

 and the sepal tips longer and more setaceous. These dif- 

 ferences give the buds of 0. grandiflora a very different 

 appearance from those of 0. Larnarckiana, so that even 

 in ordinary herbarium material there is not the slightest 

 ditliculty "m distinguishing them. 



These contrasting flower characters are brought to- 

 gether for greater convenience of reference, in the table 

 below : 



