16 POLYGONACE^E. Nemacaulis. 



incurved orbicular cotyledons. A slender annual, with spatulate white-woolly 

 mostly radical leaves and no stipules, stems sparingly and divaricately branched, 

 and very small flowers in crowded sessile subglobose clusters in the axils and along 

 the naked branches. 



1. N. Nuttallii, Benth. Stems prostrate or ascending, a half to a foot long, 

 glabrate, reddish : leaves narrowly spatulate, an inch or two long, including the 

 petiole, densely woolly on both sides, radical with usually a few small ones in the 

 axils of the short oblong herbaceous verticillate bracts which subtend the branches : 

 bractlets of the flower-clusters obovate to spatulate, a line long or less, the outer 

 without flowers, the inner smaller, glabrous outside, very woolly within : flowers 

 yellowish, less than a half line long and slightly exceeding the bractlets, shortly 

 pedicellate, glabrous ; inner segments broadest : akene a third of a line long. 

 DC. Prodr. xiv. 23 ; Gray, Proc. Am. Acad. viii. 146. N. denudata & foliosa, 

 Nutt. in Journ. Acad. Philad. 2 ser. i. 168. 



On the sandy beach near San Diego, Nuttall, Cooper, Cleveland. 



5. ERIOGONUM, Michx. 



Flowers perfect, involucrate ; involucre campanulate, turbinate or oblong, 4-8- 

 toothed or lobed, without awns, usually many-flowered (rarely 1 - few-flowered) ; the 

 more or less exserted pedicels intermixed with scarious narrow or setaceous bracts or 

 bractlets. Perianth 6-parted or deeply 6-cleft, colored, enclosing the akene. Sta- 

 mens 9, upon the base of the perianth. Styles 3 : stigmas capitate. Akene triangular 

 (rarely lenticular), sometimes 3-winged. Embryo straight and axile, or (in all Califor- 

 nian species) more or less excentric and incurved ; cotyledons foliaceous, mostly 

 shorter than the radicle. Annuals and herbaceous or somewhat woody perennials, 

 with radical or alternate or verticillate entire leaves, without stipules; varying 

 greatly in habit of growth, but readily distinguishable from other genera. The 99 

 species are confined exclusively (excepting two in the Southern Atlantic States and 

 two Mexican ones) to the region between the Mississippi River and the Pacific 

 Ocean. Torr. & Gray, Revis. Eriog. in Proc. Am. Acad. viii. 146. Watson, Proc. 

 Am. Acad. xii. 254. 



* Involucres nerveless, 4 -8-lobed or -toothed : bracts foliaceous, 2 to 5 or more, not regularly 



ternate. 



Perennials : peduncle naked, or verticillate-bracteate in the middle 

 (in nos. 2, 3 & 13), bearing a simple or compound umbel or 

 head or a solitary involucre : base of flower stipe-like. 

 Involucres deeply lobed ; lobes becoming reflexed. 



Flowers pubescent : involucres mostly solitary : low, cespitose, 



with leaves tomentose both sides. 



Dwarf, densely matted : leaves ovate- to oblong-spatulate. 1. E. C-ESPITOSUM. 



Larger, more diffuse : peduncles (3 or 4 inches high) with a 



whorl of leaves in the middle. 2. E. DOUGLASII. 



Similar, but leaves linear-spatulate, often revolute : often 



with 2- 4-rayed umbel, lateral rays bracteate. 3. E. SPH^ROCEPHALUM. 



Flowers glabrous : umbel simple or compound : diffusely branched 

 at base ; leaves glabrate above, oblanceolate or spatulate. 



Tomentose : umbel simple, of 3 to 10 naked rays. 4. E. UMBELLATUM. 



Glabrous : umbel few-rayed, the lateral rays bracted in the 



middle and often divided. 5. E. TORREYANUM. 



Tomentose : rays 2 to 4, usually and often repeatedly cymose- 



divided : nodes all bracteate. 6. E. STELLATUM. 



