162 



BRASSICACEAE. 



9. DIPLOTAXIS DC. 



Herbs, with pinnatifid or lobed leaves, and rather large yellow flowers in 

 terminal racemes. Silique elongated, linear, flat or flattish, short-beaked or 

 beakless, the valves mostly 1-nerved. Style usually slender. Seeds in two 

 complete or incomplete rows in each cavity of the silique, marginless; cotyle- 

 dons conduplicate. [Greek, referring to the double rows of seeds.] About 20 

 species, natives of the Old World. Type species: Diplotaxis tenuifolia (L.) DC. 

 The flattened pods with seeds in two rows distinguish this genus from the 

 Mustards. 



1. Diplotaxis muralis (L.) 

 DC. Sand Rocket. (Fig. 177.) 

 Branched from the base, spar- 

 ingly hispid or glabrous, leafy 

 only below. Leaves oblanceo- 

 late, sinuate-lobed or pinnatifid, 

 2'— 1' long, narrowed at the base, 

 mostly slender-petioled ; flowers 

 6"-8" broad; pod about 1' long 

 and 1" wide, erect, flattish; fruit- 

 ing pedicels, 4"-8" long. 



Abundant in waste and culti- 

 vated grounds on St. David's Island, 

 1909 and in cultivated ground near 

 Wreck Hill, 1912. Naturalized from 

 Europe. Naturalized in the eastern 

 Fnited States. Flowers in spring. 

 This plant may become a pernicious 

 weed, as the seeds germinate readily. 



10. CAIOLE [Tourn.] Mill. 



Annual, glabrous fleshy branching herbs, with petioled leaves and purplish 

 racemose flowers. Siliques elongated, sessile, flattened or ridged, indehiscent, 

 2-jointed, the joints 1-celled and mostly 1-seeded. Style none; cotyledons 

 accumbent. [Old Arabic name.] A genus of several species, natives of sea 

 and lake shores of Europe and North America. Type species: Bunias Cakile L. 

 The curious two- jointed pods which do not split open are an interesting 

 feature of these plants. 



