254 PROCEEDINGS OF THE AMERICAN ACADEMY 



pedicels filiform, 3 to 6 lines long, obscurely jointed near the base : 

 valves without grains, broadly cordate with a very shallow sinus, 

 becoming about 3 lines in diameter, often denticulate near the base : 

 akene a line and a half long. — From Alaska to Northern California, 

 eastward to the Saskatchewan and Labrador, and southward in the 

 mountains to Colorado and New Mexico. It has hitherto been referred 

 to R. longifolius, DC, but that Old World species has narrow and very 

 undulate leaves, broadest near the middle, the pedicels with a tumid 

 joint below the middle, and the valves more deeply cordate. 



ERIOGONUM, Michx. During the seven years that have elapsed 

 since the thorough revision of the Eriogonece by Dr. Gray, published 

 in the eighth volume of these Proceedings, so much additional mate- 

 rial has been collected and so many new species have been described 

 that it seems not useless to give again a summary of the two larger 

 genera of the group. Some modifications are made in the arrange- 

 ment of the species in Eriogonum, based mainly upon the characters 

 of the bracts and involucres, by which the genus is divided naturally 

 into three princijjal sections, as follows : — 



§ 1. Involucres not nerved or angled, 4-8-toothed or -lobed, more or less 

 broadly turbinate (mostly 2 lines long or more) : bracts foliaceous, indefinite 

 in number (2 to 5 or more), rarely somewhat ternate. Mostly perennial. — 

 Ederiogonum. 



* Tall perennials with scarcely branching caudex, more or less villous-pubescent 

 or silky, with long oblanceolate alternate leaves and alternate branches, 

 loosely di- or trichotomous above : bracts small : involucres pedunculate, soli- 

 tary, with 5 erect teeth : akenes large (2 to 4 lines long): embryo straight 

 and axile. 



H- Akenes membranously winged : flowers not attenuate at base, nor much en- 

 larged in fruit. — (§ Alata, Benth., excl. sp.) 



1. E. ALATUM, Torr. Loosely silky-villous throughout, or the 

 leaves nearly glabrous except on the margin and midrib : flowers a 

 line long, yellow, nearly glabrous, abrupt at base : akene winged the 

 whole length, 3 lines long. — Nebraska to W. Texas and Arizona. 



2. E. TRISTE, Watson, Proc. Am. Acad. x. 347. Similar, but 

 nearly glabrous : flowers deep purple, glabrous, somewhat narrowed at 

 base: akene 4 lines long. — S. Utah. 



3. E. HiERACiFOLiUM, Benth. Hoary-pubescent throughout and 

 leaves usually tomentose beneath : flowers pubescent, yellow or rose- 

 colored, 1^ lines long (or 2 lines in fruit), abruptly narrowed at base : 

 akenes 2^ lines long, winged above the middle. — W. Texas and Rio 

 Grande Valley. 



