IO4 RANUNCULACEAE. 



141. THALICTRUM. MEADOW RUE. 



Erect perennial herbs; leaves 2-3-ternately compound, radical 

 and cauline, the latter alternate; flowers perfect, polygamous or 

 dioecious, generally small, greenish-white, in corymbs, panicles or 

 racemes; sepals 4 or 5, petal-like or greenish, dull-colored; petals 

 none; stamens numerous; pistils 4-15, commonly few, 1-ovuled; 

 akenes capitate, grooved or ribbed, inflated. 



Leaflets thin; inflorescence loose. T. occidentale. 



Leaflets rather thick, veiny ; inflorescence narrow, close. T. venulosum. 



Thalictrum occidentale Gray. Dioecious; stems 50-100 cm. tall; leaves 

 ternately decompound; leaflets oblong, obovate or orbicular, mostly petioled, 

 incisely dentate at the apex, glabrous, 1-2 cm. long; panicle loose; sepals 

 elliptic-cuneate, greenish; filaments very slender; anthers linear, slender- 

 pointed; akenes 6-12, "in loose clusters, stipitate, lanceolate, long-acuminate, 

 3-nerved on each side, the mid-nerve somewhat salient, 6-8 mm. long. Moist 

 woods and copses. 



Thalictrum venulosum Trel. Similar to T. occidentale; leaves glaucous, 

 the leaflets thicker, veiny beneath, short-petioled and somewhat crowded; 

 inflorescence narrow, rather compact; akenes sessile, thick walled, the ribs 

 prominent. In low meadows, much rarer than T. occidentale. 



142. TRAUTVETTERIA. 



Tall erect perennial herbs; leaves palmately-lobed, the radical 

 large and long-petioled ; the cauline few, short-petioled or sessile ; 

 flowers white, in corymbs; sepals 3-5, broad, concave; petals 

 none; stamens numerous; pistils numerous, 1-ovuled; akenes 

 capitate, sharply-angled, inflated, tipped with minute styles. 



Trautvetteria grandis Nutt. Stems 30-50 cm. tall, glabrous or nearly so; 

 leaves broader than long, 8-30 cm. across, 5-9-cleft, the lobes oblong or obovate, 

 acute, incisely lobed and toothed; akenes smooth, ovate, three-angled, tipped 

 with a slender recurved beak. In moist places in the mountains. 



143. MYOSURUS. MOUSE TAIL. 



Very small annual herbs ; leaves entire, linear or at first spatu- 

 late, in a basal tuft; scapes simple, 1 -flowered; sepals 5, spurred 

 at the base; petals 5, greenish-yellow, with long nectariferous 

 claws, or none; stamens 5-20; pistils numerous, borne on a 

 central axis, the receptacle, which becomes greatly elongated in 

 fruit; ovule 1. 



Myosurus apetalus Gay. Scapes 3-8 cm. high; leaves linear-spatulate, 

 half the length of the scapes; fruiting spikes 2-6 mm. long; akenes oblong, 

 the back with a prominent keel which is prolonged into a stout beak as long 

 as the body. The plant usually becomes reddish when mature and often 

 covers considerable areas. 



Myosurus apetalus lepturus Gray. Taller, 10-20 cm. tall; leaves linear, 

 one fourth as long as the scapes; fruiting spikes slender, 1-5 cm. long; akenes 

 scarcely keeled on the back, the beak much shorter than the body. In dried-up 

 ponds, infrequent. 



