22 CRUCIFEILE. 



than the other four, rarely only 4 or 2. Ovary 2-celled by a thin partition, rarely 1- 

 celled. Leaves alternate, and flowers usually in racemes without bracts. 



A careful examination of the fruit is usually necessary for a determination of the 

 species in this difficult order. Key to genera and species, p. 84. 



In Tropidocarpum only are the flowers solitary and axillary. 



T. capparideum, Greene, is distinguished by inflated pods ranch shorter than 

 represented at d in the figure, and opening from above. Perhaps only a variety. 



Under Thelypodium the following species may be added: T. Hookeri, Greene. 

 Distinguished from T. flavescens by broader sepals which with the pedicils are smooth; 

 broader claw and narrower blade of petals and longer pods: perhaps only the Monte 

 Diablo form of the latter species. T. rigidum, Greene. Stout and very rigid, 1-3 feet 

 high; pods nearly sessile, 1| inch long, rigid, sharply tipped with the short style. 

 Monte Diablo. 



The perennial species of Cardamine in Bay Region Botany may be considered 

 forms of C. paucisecta. The species of Streptanthus are so variable that botanists differ 

 widely as to their limits. Their irregular flowers make them worthy of the special 

 attention of students who are interested in the relations between flowers and insects. 

 What insects are accommodated by this irregularity? The flowers vary from white to 

 nearly black in color. Are these forms for they certainly were one form and color 

 not long ago found growing together? Are they visited by different insects? 



Prof. Greene adds in Bay- Reg. Bot. seven species, viz: 



S. barbigef. Stem leaves linear, entire; sepals equal, greenish, the acuminate tips 

 whitish and recurved: petals white: filaments dark purple. Near St. Helena. 



S. suffrutescens. Perennial steins with a stout leafy persistent trunk, bearing 

 longer flowering branches: stem-leaves cuneate-obovate, coarsely serrate; floral leaves, 

 round cordate or narrower. Collected by Bioletti on Hood's Peak, Sonoma Co. 



S. albidus. Distinguished from S. niger by white not dark purple sepals, the 

 anthers of the united pair of stamens bearing pollen. Found only on Oak Hills near 

 San Jose. 



S. Mildredae. Slender, less than two feet high: small flowers, very dark metallic, 

 purple: slender petals, white-margined. Mt. Hamilton. 



S. Biolettii. Similar to S. glandulosus: more slender racemes, not one-sided: sepals 

 darker, smaller. Hood's Peak. 



S. pulchellus. A foot or less in height, much branched: slender leaves with a few 

 coarse teeth: calyx lilac purple, the sepals nearly equal. Mt. Tamalpais, on south side. 



S. secundus. Lower leaves pinnately lobed or toothed: racemes of flesh -colored 

 flowers, one-sided: lower sepal clawed. North side of Mt. Tamalpais. 



These, excepting possibly the first two, may be considered as forms of S. Glandu- 

 losus. 



