108 POLYGONACEAE. 



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



woody rootstock. 3. R. venosns. 



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. hymenosepalns. 



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



510 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 rounded 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. densiflorits. 



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



g. R. sitbalpinits. 



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. u. R. altissimns. 



All three petals bearing tubercles. 



Leaves wavy-margined, dark green, not glaucescent. 



12. R. crisp tis. 



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



Inner perianth-lobes in fruit spinulose on the margin. 



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



14. R. obtusifolius. 

 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 Torr. 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. 



