152 



PO L Y G N ACE M . 



Mt. Diablo and Mt. Hamilton, acc. to Greene; Sierra Nevada. 



0. inermis Wats, has been doubtfully credited to Mt. Diablo. — 

 Bracts 2 or 3 lines long; involucres shortly pediceled, 4-cleft nearly 

 to the base, awnless; flowers rose-color, £ line long; inner segments 

 smaller and retuse. 



5. ERIOGONUM Michx. 

 Annuals or perennials with radical or alternate or whorled leaves 

 without stipules, the upper bract-like. Flowers perfect, involucrate. 

 Involucre 4 to 8-toothed or -lobed, several to many-flowered; pedicels 

 more or less exserted, intermixed with narrow scarious bracts. Calyx 

 6-parted or -cleft, colored, persistent about the achene. Stamens 9, 

 inserted on the base of the calyx. Styles 3; stigmas capitate. 

 Achene triangular, except in a few species. Embryo straight, in the 

 axis of scanty endosperm; cotyledons foliaceous. (Greek erion, wool, 

 and gonu, knee or joint, the nodes hairy in some species.) 



Involucres turbinate, deeply lobed, the lobes becoming reflexed, disposed in a 

 simple or compound umbel, raised on a scape-like peduncle from a leafy 

 perennial and more or less woody base; calyx narrowed to a stipe-like base; 

 filaments hairy below. 

 Woody base much branched; leaves obovate to oblanceolate; acute, % to 1 



in. long 1. E. stellatum. 



Woody base very short and simple; leaves oblong-ovate, cordate at base, \% 



to* 2 in. long . 2. E. composition. 



Involucres cylindric-lurbinnte or prismatic, 5 to 6-nerved, with erect teeth, 

 always sessile, either disposed in heads in a cymose panicle or umbel-iike 

 inflorescence or solitary and scattered along the virgate branches; calyx not 

 attenuate at base; filaments usually glabnm-. 

 Peduncles scape-like; involucres capitate-clustered; perennials. 

 Heads 1 to 3 or 4, large and terminal, or the peduncle forked and umbel- 

 like; bractlets densely villous-tomentose 3. E. lat {folium. 



Heads scattered in an ample cymose panicle; bractlets glabrous 



4. E. nudum. 



Stems parted from the base or above the base into mostly elongated flowering 

 branches, along which the solitary involucres are scattered, rarely 2 to 

 several in a cluster. 

 Perennials, with short woody stems which are densely leafy. 

 Leaves obovate or oblanceolate, acute; bracts all small and triangular . . 



5. E. Wrightii 



var. tmchygonum. 

 Leaves roundish; lower bracts subfoliaceous . ... 6. E. saxatile. 

 Annuals; leaves mostly in a rosette at base. 

 Inflorescence somewhat umbel-like, the 2 to 4 rays once or twice di- or tri- 



chotoraous, or 1 or 2 simple ...I.E. truncatum. 



Plants for the most part di- or tri-chotomously parted from the b;ise or 

 the middle, with the flowering branches much elongated and the 

 involucres s attered along them. 

 Involucres narrow or turbinate. 1 to 1% lines long; flowers glabrous; 

 often diffusely branched. 

 Stems and inflorescence glabrous; teeth of the involucre inconspicuous 



9. E. vimineum. 



White-woolly throughout; teeth of the involucre prominent 



8. E. gi-acite. 



Involucres cylindric, 2 lines lo"g. 

 Flowers glabrous; erect and strictly branched . 10. E. virgatum. 

 Flowers villous on the outside; more or L-ss umbellately branched, 



sometimes very diffnse 11. E. dasyant/iemum. 



Involucres turbinate, on filiform pedicels; panicle repea.edly dichotomous, com- 

 monly leafy at the nodes 12. E. angulosum. 



1. E. stellatum Benth. Somewhat toraentose, the leaves densely 



