108 POLYGONACEAE. 



Inner perianth-lobes in fruit over 2 cm. broad, plants with deep-seated 



woody rootstock. 3. R. vcnosus. 



Inner perianth-lobes in fruit less than 1.5 cm. in diameter. 



Plants with clusters of tuberous roots ; inner perianth-lobes in fruit 1-1.5 

 cm. broad. 

 Achene about 7 mm. long ; inner perianth-lobes in fruit broader than 



long; plant low. 4- R- salinus. 



Achenes about 5 mm. long ; inner perianth-lobes in fruit longer than 

 broad. 5. R. hymenoscpalus. 



Plants with taproots or thickened rootstocks ; inner perianth-lobes in fruit 

 5-10 mm. wide. 

 Plants low, less than 3 dm. high, with short tuber-like rootstock ; fruit 

 maturing before the inner perianth-lobes become enlarged. 



6. R. praecox. 

 Plant tall, not with a tuber-like rootstock ; inner perianth-lobes well 

 enlarged in fruit. 

 Inner perianth-lobes in fruit with roimded apex, not conspicuously 



punctate. 7. R. occidentalis. 



Inner perianth-lobes abruptly pointed, conspicuously punctate. 



Fruiting inner perianth-lobes broader than long, sinuate on the 



margin. 8. R. densiftorus. 



Fruiting inner perianth-lobes longer than broad, sharply dentate. 



9. R. subalpinus. 

 Inner perianth-lobes or at least one of them bearing a tubercle in fruit. 

 Only one tubercled. 



Leaves dark green, more or less crisp ; fruiting inner perianth-lobes 8-9 



mm. broad, reniform. 10. R. Patientia. 



Leaves pale green, not crisp ; fruiting inner perianth-lobes 5-6 mm. 

 broad, deltoid ovate. 11. R. altissimus. 



All three petals bearing tubercles. 



Leaves wavy-margined, dark green, not glauccscent. 



12. R. crispus. 

 Leaves flat, light green and glaucescent. 13. R. salicifolius. 



Inner perianth-lobes in fruit spinulose on the margin. 



Tall plants ; lower leaf-blades cordate at the base ; one tubercle. 



14. R. ohtusif alius. 

 Low plants ; lower leaf-blades narrowed at the base ; 3 tubercles. 



15. R. persicarioides. 



1. Rumex Asetosella L.' In waste places, old fields, roadsides, etc., from 

 Lab. and Alaska to Fla. and Calif. ; introduced from Europe. — Alt. about 5000 

 ft— Boulder. 



2. Rumex pauciflorus Nutt. {R. Geyeri (Meisn.) Trelease.) In meadows 

 from Mont, and Wash, to Colo, and Calif. — Continental Divide, Larimer Co. ; 

 Steamboat Springs ; Rabbit-Ears. 



3. Rumex venosus Pursh. In sandy soil from Ass. and Wash, to Kans. and 

 Nev. — Alt. 4000-8000 ft. — Cucharas River, below La Veta; Fort Collins; 

 Pleasant Valley; upper part of Platte; Miller's ranch; Bingham Hill; Pueblo; 

 Wray; Colorado Springs. 



4. Rumex salinus A. Nels. In sandy soil in Wyo. and Colo. — Palisades. 



5. Rumex hymenosepalus Torn In sandy soil from Ind. Terr, and Utah 

 to Tex. and Calif. — Alt. 4000-9000 ft. — Grayback mining camps ; Grand Junc- 

 tion. 



6. Rumex praecox Rydb. Along brooks in the higher mountains of Wyo. 

 and Colo. — Alt. 8000-10,000 ft. — Grayback mining camps ; Bob Creek, west 

 La Plata Mountains. 



