I It") CRUCIFER.E. 



Geographical Distribution and Division. A genus of a dozen or 

 more known species, natives of the drier and nearly unwooded portions of 

 temperate North America west of the Mississippi, from Arkansas to Cali- 

 fornia. Two well-marked sections have been recognized, namely, — 



$ 1. Eustkeptanthus. — Petals with a broad dilated lamina. Calyx 

 loosely erect. 



§2. Euclisia, Nutt. — Limb of the petals narrow (often linear) and un- 

 dulate as well as the claw. Calyx erect, often inflated-eonnivent. 



Note. The areolation in S. bracteatus and S. obtusifolius consists of 

 vertical linear or oblong cells bounded by even lines ; that of S. heterophyl- 

 lus ? (PI. Coult.) is similar, except that the cells are nearly quadrate ; S. 

 glandulosus exhibits long and very irregular curved .cells, bounded by sinu- 

 ous lines of uniform strength ; while, in S. hyacinthoides, the lines are of 

 very unequal strength, some of them appearing like veins, and branching 

 so as to form minute amorphous reticulations, as shown in Plate 61, fig. 8. 



PLATE 60. Streptanthus bracteatus, n. sp. (Texas, Lindheimer) ; 

 — a branch, with a cauline leaf, of the natural size. 

 1. A sepal, inside view ; and 2, a petal, enlarged. 



3. Stamens and pistil, enlarged. 



4. A mature silique of S. obtusifolius, Nutt. (Arkansas, Herb. Torr.) ; 



of the natural size. 



5. Base of an enlarged silique, transversely divided. 



6. Tissue from the partition, highly magnified. 



7. A magnified seed, divided transversely. 



8. Embryo detached entire, and enlarged. 



PLATE 61. Streptanthus (Euclisia) hyacinthoides, Hook.; — from 

 Texas; the flowering summit, of the natural size. 



1. A flower, enlarged. 



2. A sepal; and 3, a petal, more enlarged. 



4. Stamens (one of the larger pairs united), and pistil, enlarged. 



5. A silique, of the natural size. 



6. Summit of a silique, enlarged, showing a transverse section. 



7. Base of a replum, with three seeds, enlarged, two of them cut across. 



8. Tissue from the partition, highly magnified (the stronger lines are rep- 



resented somewhat too continuous and direct). 



