EXPLANATION OF THE PLATES. 391 



closing the two connate ovaries, with their styles cut away 

 near their base ; both figures magnified. 



2, Ceplialanthus occidentalis, a flower-head, the natural 

 size ; 2<^, a flower with the style much exserted ; 2b, the 

 corolla laid open, showing the included stamens ; both 

 magnified. 



3, Oldenlandia cserulea, a small specimen of the natu- 

 ral size ; Za, corolla laid open, to show the included sta- 

 mens ; 35, the pistil with the ovary vertically cut open ; 

 both figures magnified. 



4, Valeriana pauciflora, a branchlet with a 'cymous clus- 

 ter of flowers, the natural size ; ^a, a flower detached, 

 with a few plumose bristles of the calyx-limb unrolled ; 

 45, the ovary vertically divided, showing the embryo ; the 

 bristles of the calyx broken away ; both figures magnified. 



5, Dipsacus sylvestris, a small head of flowers ; ha, lon- 

 gitudinal section of the receptacle, all the flowers with 

 their bracts, save three, removed ; both figures the na- 

 tural size. 



6, Mikania scandens, part of a corymb with a few 

 flower-lieads, the natural size ; 6<^, a head detached, with 

 an involucre of four scales and four tubular flowers ; 65, 

 one of the flowers separate ; 6<?, the stamen-tube laid open ; 

 all more or less magnified. 



7, Chrysopsis falcata, two flower-heads of the natural 

 size ; 7a, a tubular perfect flower taken from the disk ; 

 75, a ligulate flower of the ray, pistillate ; both figures 

 magnified. 



8, Liatris squarrosa, a head, discoid; the scales of the 

 involucre with elongated, spreading tips. 



9, Nabalus Fraseri, part of the corymbose panicle, the 

 natural size ; 9a, one of the liguliflorous heads detached ; 

 95, one of its flowers ; both figures magnified. 



