Trelease.] 



294 



[March 17, 



gamous. Sepals 4-5, petaloid in some species ; stamens indefinite ; 

 carpels numerous (rarely few), inserted on a small receptacle; 

 ovule solitary, pendulous ; stigma unilateral ; achenia tailless, 

 marked on each side with a few nerves, ribs or deep grooves, 

 terete or compressed, rarely inflated or (in some European species) 

 subtriquetrous. — Bentb. & Hook., Gen. Plant., i, 4. 



In distinguishing the species, the most valuable characters are 



Fig. 1. Foliage of Thalictrum. 



1. T. clavatum. 2. T. spar siflor urn. 3. T. alpinum. 4. T. minus. 5. T. polygamum. 

 6. T. purpurascens. 7. T. debile ; the smaller leaflets from var. Texanum. 8. T. 

 dioicum. 9. T. venulosum. 10. T. occidentale. 11. T. Fendleri. 12. T. Fendleri, var. 

 Wrightii. 13. T. poly carpum.— Reduced one-half. 



drawn from the condition of the flowers, — whether perfect, poly- 

 gamo-dioecious, i.,e., dioecious but regularly with a limited num- 

 ber of stamens in the flowers of some fertile plants (less commonly 

 with abortive ? pistils in staminate flowers), or dioecious ; the length 

 and form of the filaments, which vary from filiform with a slight 

 widening toward the anther to narrowly, or, in T. clavatum, 

 broadly and abruptly spatulate, and of the anthers, which are ellip- 



