689 Rydberg : Studies on the Rocky Mountain Flora 



Key to the Speclen 



Leaves from cordate to broadly ovate-lanceolate : all distinctly petioled. 



Leaves cordate. I. A. nydaginea. 



Leaves ovate, rounded or cuneate at the base. 2. A. floribunda. 



Leaves ovate-lanceolate, oblong or linear, sessile or only the lower short- petioled. 

 Involucres in open terminal cymes. 



Stem more or less hirsute as well as viscid. 



Leaves ovate or broadly oblong, as well as the stem conspicuously hir- 

 sute. 3. A. hirsnia. 

 Leaves linear-lanceolate, almost glabrous ; stem sparingly hirsute or 

 glabrous except under the nodes. 4. A. pilosa. 

 Stem glabrous below, not hirsute, viscid-puberulent above. 



Flowers solitary in the involucre on short slender pedicels ; fruit nearly 



glabrous. 5. A. glabra. 



Flowers 2-3 in the involucres, subsessile ; fruit decidedly pubescent. 



Leaves of the cymes much reduced and bract-like, upper portion of 



the stem densely and finely puberulent. 6. A. bradeata. 



Leaves of the cymes neither much reduced nor bract-like. 



Leaves erect or ascending ; lobes of the involucre rounded or 

 broadly triangular-ovate. 

 Plant prostrate or diffuse ; involucres and branches of the 



inflorescence densely viscid hairy. 7. A. diffusa. 

 Plants more simple, erect or ascending ; branches of the 

 inflorescence usually merely viscid-puberulent. 

 Leaves from ovate or obovate to linear-lanceolate, 

 usually over 5 mm. wide. 8. A. lanceolata. 



Leaves narrowly linear, less than 5 mm. wide. 



9. A. linearis. 

 Leaves divergent ; lobes of the involucre elliptic or oval. 



10. A. divaricata. 

 Involucres on solitary axillary peduncles, rarely also in small dense terminal clusters. 

 Leaves oblong, lanceolate or linear-lanceolate. 

 Stem hirsute. 

 Stem glabrous. 

 Leaves narrowly linear. 



I. Allionia nyctaginea Michx. Fl. Bor. Am. 

 OxybapJius nyctagiiicus Sweet, Hort. Brit, i : 

 A well-known and common plant growing in rich soil from 

 Illinois and Saskatchewan to Wyoming, New Mexico and 

 Louisiana.* 



2. Allionia floribunda (Choisy) Kuntze, Rev. Gen. 533. 1891 

 A. ovata Pursh, Fl. Am. Sept. i : 97. 18 14. Not Oxybaphus 

 ovatiis Vahl. 1806. 



* Allionia Cervantesii has been reported from Colorado, but the specimens on which 

 this assertion has been made belong in all cases I know to Allioniella oxybaphoides. 



