14i FLORA OF TEXAS. 



nate, the radical ones long-petioled. Flowers axillary or 

 somewhat corymbed, white or yellow. 



§ 1. PeUUs white, with yellow pit at the base; achenia rugose. 



R AQUATiLis, L. Stems 1-2 feet or more in length, 

 slender, weak, round, smooth, jointed. Leaves petioled, 

 divided into an indefinite number of capillary segments, in 

 outline roundish, and ^'-1' diameter. Flowers axillary, 

 remote, long peduncled. Sluggish streams and ponds. 

 July, August. 



§ 2. Petals yellow, with a small scale at the base. 

 * Achenia muricate ; annuals. 



R. PARViFLORUS. Silky-pubescent ; leaves small, the 

 lower ones circular, 3-lobed, acutely toothed ; the upper 

 3-parted or entire ; flowers quite small, the yellow petals 3-5, 

 as long as the reflexed sepals ; achenia narrowly margined, 

 pointed with the short, recurved style. Waste places. 

 March-May. Stem 6-12' high, erect, branching. Leaves 

 rarely V wide. 



** Achenia smooth ; chiefly perennials. 

 t Leaves undivided. 



R. OBLONGiFOLius. Leaves petiolate, denticulate, lower 

 ones oblong-oval, upper ones linear-lanceolate; petals a 

 little longer than the calyx ; carpels globose, not pointed, 

 smooth. — Drummond. 



R. Texeksis. Stems erect, diffuse, branching. Leaves 

 lanceolate and lance-ovate. Floivers minute, numerous. 

 Stamens about 20. Petals yellow, less than 1" long. Car- 

 pel minute, pointless, in round heads. — Engl. 



tt Leaves (at least those of the stem) alternately lobed or divided. 

 tt Petals small, not exceeding the calyx. 



R. AFFiN^is. Radical leaves petioled, pedately multifid ; 

 cauline ones subsessile, digitate, with linear lobes; stem 

 erect, few-flowered; calyx and ovary pubescent; carpels 

 with recurved beak, disposed in oblong-cylindrical heads. 

 June-August. New Mexico. — Bigelow. 



