254 CONTEIBUTIONS FROM THE NATIONAL HEEBAKIUM. 



10. THALICTRUM L. Meadow rue. 



Low or tall perennial herbs with alternate, twice or thrice ternately compound 

 leaves, the petioles dilated at the base; inflorescence corymbose or paniculate, often 

 polygamous or dioecious; sepals 4 or 5, petal-like, greenish, inconspicuous; petals 

 none; achenes 4 to 15, grooveld or ribbed or inflated. 



KEY TO THE SPECIES. 



Flowers perfect; plants small, 20 cm. high or less 1. T. cheilanthoides. 



Flowers dicEcious or polygamous; plants large, 30 to 100 cm. high. 



Flowers polygamous; achenes not flattened, thick-walled; 



ribs thick, separated by acute grooves; cauline leaves 



sessile 2. T. dasycarpum. 



Flowers dioecious; achenes flattened, thin-walled; ribs thin, 

 separated by wide rounded gl'ooves; cauline leaves 

 petiolate. 

 Leaflets very large, 20 to 40 mm. long; achenes symmet- 

 rical or nearly so 3. T. occidentale. 



Leaflets seldom more than 15 mm. long, usually less; 

 achenes asymmetrical. 

 Leaflets large; achenes almost twice as long as broad; 



pedicels and fruit glandular 4. T. fendleri. 



Leaflets small; achenes but little longer than broad; 



pedicels and fruit usually glabrous 5. T. wrightii. 



1. ThaKctrum cheilanthoides Greene, Leaflets 2: 89. 1910. 



Type locality: Pecos Baldy, New Mexico. Typecollectedby Standley (no. 4324). 

 Range: Known only from type locality, in the Arctic-Alpine Zone. 

 This is possibly not distinct from T. alpinum L. 



2. Thalictrum dasycarpum Fisch. & Lall. in Fisch. & Mey. Ind. Sem. Hort. 



Petrop. 8: 72. 1841. 

 Type locality: "Hab. in America boreali, ubi sub expeditione Frankliniana 

 semina collecta sunt." 

 Range : British America to northern New Mexico. 

 New Mexico: Aztec (Griffin). Wet ground. 



3. Thalictrum occidentale A. Gray, Proc. Amer. Acad. 8: 372. 1872. 

 Type locality: Vancouver Island. 



Range: British America to California and New Mexico. 



New Mexico: Four miles south of Tijeras {Herrick). Movmtains, in the Transition 

 Zone. 



4. Thalictrum fendleri Engehn. in A. Gray, Mem. Amer. Acad. n. ser. 4: 5. 1849. 

 Type locality: Damp, shady places in the mountains around Santa Fe, New 



Mexico. Type collected by Fendler (no. 13). 



Range: Wyoming to Arizona and New Mexico. 



New Mexico: Carrizo Mountains; Tunitcha Mountains; Chama; Raton; Johnsons 

 Mesa; Sierra Grande; Upper Pecos; Mogollon Mountains. Meadows and thickets in 

 the mountains, Transition and Canadian zones. 



5. ThaUctrum wrightii A. Gray, PI. Wright. 2: 7. 1853. 

 Thalictrum fendleri wrightii Trel. in A. Gray, Syn. Fl. 1': 16. 1895. 

 Type locality: Mountain ravine at Santa Cruz, Sonora, Mexico. 

 Range: New Mexico and Arizona and southward. 



New Mexico: North of Ramah; Pinos Altos Mountains; Luna; 'Wlieelers Ranch; 

 Hanover Mountain; Organ Mountains; White and Sacramento mountains. Moim- 

 tains, in the Transition Zone. 



