FLOWERING PLANTS AND FERNS OF ARIZONA 331 



14. Ranunculus arizonicus Lemmon ex A. Gray, Amer. Acad. Arts 

 and Sci. Proc. 21: 370. 1886. 



Ranunculus nudatus Greene, Leaflets 1: 211. 1906. 



Greenlee County to the Chiricahua, Huachuca, and Patagonia 

 Mountains (Cochise and Santa Cruz Counties), 5,000 to 7,000 feet, dry 

 situations, summer, type from Rucker Valley, Cochise County 

 (Lemmon 585). Southwestern New Mexico and southeastern Arizona. 



Species remarkable in this genus for its habitat in dry situations. 



After this publication went to press, it was discovered that an apetalous small 

 form of Ranunculus pedatifidus J. E. Smith had been collected on the San Fran- 

 cisco Peaks at 12,000 feet (Little 4632). This form has lobed instead of divided 

 leaves. 



Furthermore, an undescribed species of Ranunculus related to R. alismaefolius 

 Geyer, has been found in Coconino County, near the Grand Canycn (Collom in 

 1940), between Mormon Lake and Sedona (M. Wetherill), and at Jacobs Lake 

 (Maguire 13550), occurring also in the La Sal Mountains, southeastern Utah. 

 It is distinguished from R. glaberrimus var. ellipticus by the ovoid, short-pubescent 

 receptacle, the entire cauline leaves, and the large achenes which are about 3.5 

 mm. long and measure 2.2 mm. dorsoventrally and 1.5 mm. laterally. It is dis- 

 tinguished from R. alismaefolius Geyer and its varieties by the smaller number of 

 roots occurring in solitary plants, that is, 6 to 10 instead of 15 to 30, the pubescent 

 receptacle, the flat, winged stalk of the achene, and the pubescent fruits. Hairy 

 achenes occur in R. alisaefolius only in the variety lemmoni. The unnamed 

 species is intermediate between the sections Epirotes and Flammula and it forms 

 a strong connecting link between them. 



Also R. bongardi Greene var. tenellus (Nutt.) Greene has been discovered 

 recently on the north rim of the Grand Canyon (Collom in 1940). It is distin- 

 guished from other Arizona species of the section Chrysanthe as follows: Petals 5, 

 not more than 4 mm. long; achene beaks not more than 2 mm. long, strongly 

 recurved; receptacle glabrous, in fruit not more than 2.5 times the length in 

 anthesis; head of achenes hemispherical or globose. 



12. THALICTRUM. Meadowrue. 



Plants herbaceous, perennial; leaves alternate large, twice or thrice 

 ternate with numerous cleft or shallowly lobed leaflets, the basal 

 leaves long-stalked ; flowers mostly unisexual, small, greenish or yellow- 

 ish, in terminal panicles; perianth of 4 or 5 caducous segments, these 

 all alike; petals none; stamens numerous; pistils few, becoming 

 asymmetric achenes in fruit, these with prominent longitudinal ribs 

 extending from base to apex. 



Key to the species 



1. Stem leaves sessile or very nearly so, the leaflets longer than wide, rather thick 

 and rigid, distinctly pubescent beneath; achenes moderately asymmetric; 

 stems tall 1. T. dasycarptjm. 



1. Stem leaves petioled (except sometimes the uppermost), the leaflets usually 

 wider than long, thin, not rigid, minutely puberulent or glabrate beneath; 

 achenes very asymmetric, gibbous on the ventral side 2. T. fexdleri. 



1. Thalictrum dasycarpum Fisch. and Lall.inFisch. and Mever, Index 

 Sem. Hort. Petrop. 8: 72. 1841. 

 White Mountains, Apache County (WJiitehcad 1511), Showlow, 

 Navajo County, 5,900 feet {Hough), July. Western Canada to New 

 Mexico and eastern Arizona. 



