380 COMPOSITiE. DicHiETA . 



1. D. uligincsa (Nutt. ! 1. c.) : decumbent, branching ; leaves crowded 

 rear the base, laciniate-pinnatifid ; the lobes linear; the rachis broad : rays 

 and scales of the involucre 8-12. 



St. Barbara, California, Nuttall ! April. — Plant 4-6 inches high, almost 

 aquatic. Lower leaves 2-3 inches long. Heads one-third to half an inch in 

 diameter, including the short oblong rays. Scales of the pappus often some- 

 what united ; the awns slightly dilated below, minutely serrulate-scabrous. 



2. D. tenella (Nutt.! I.e.): stem erect, simple, slender; leaves linear; 

 the upper entire ; the lower sparingly laciniate-pinnatifid towards the base ; 

 rays and scales of the involucre 5-8. 



St. Barbara, California, growing wilh D. uliginosa, Nuttall! April. — 

 Plant 3-4 inches high, resembling Burrielia gracilis. Stem and leaves 

 hairy. 



124. HYMENOXYS. Cass. diet. 55. p. 278 ; DC. prodr. 5. p. 661. 



Heads many-flowered, discoid, or often radiate ; the ray-flowers 8-10, li- 

 gulate, pistillate; those of the disk tubular, perfect. Scales of the involucre 

 in 1-2 series, appressed, nearly the length of the disk. Receptacle conical, 

 alveolate, mostly pilose or glandular. Corolla of the disk with a slender 

 (sometimes minutely glandular) tube, and an expanded 5-toothed limb; the 

 lobes glabrous, or slightly bearded. Branches of the style short, truncate 

 and minutely barbellate at the apex. Achenia usually turbinate, and silky- 

 villous. Pappus of 5-12 unequal chafTy acuminate or awned scales, min- 

 utely denticulate, mostly similar but often smaller in the ray (in § 2, awn- 

 less, or entirely wanting!). — Annual or sometimes perrennial ? (South 

 American, Mexican, and Californian) branching nearly glabrous and min- 

 utely glandular herbs, exhaling the odor of Chamomile, with rather small 

 showy heads terminating the branchlets. Leaves alternate or opposite in 

 the same plant, 1-2-pinnately parted into linear-filiform or almost capillary 

 segments. Flowers yellow. 



§ 1. Heads radiate : scales of the pxippus {at least in the disk-Jlou-ers) awned. 

 — OxTPAPPUS, DC. (Ptilomeris, Nutt.) 



1. H. Californica {Hook.) : achenia fusiform, minutely strigose ; pappus 

 of mostly 10 (8-12) small lanceolate or oblong denticulate-serrate scales; in 

 the disk-flowers terminated with long awns a little shorter than the corolla; 

 in the ray with 2-4 of the scales awned ; the others awnless and smaller ; 

 scales of the involucre lanceolate; leaves mostly opposite; the divisions 

 capillary ; the rachis often broad towards the base. — Hook. bat. mag. t. 

 3828. Ptilomeris aristata, Nutt. ! in tra7is. Amer. phiL. soc. (re. ser.) 7. p. 382. 



/?. coronaria : scales of the pappus of the ray small and acute, but all of 

 them awnless ; receptacle more hairy. — Ptilomeris coronaria, Nutt.! I. c. 



St. Diego, California, Nuttall! April. — (T) Branched from the base, mi- 

 nutely glandular-puberulent. Scales of the involucre somewhat embracing 

 the ray-achenia, which are a little incurved. Rays oblong, 2-3-toothed at 

 the apex. Achenia linear-obconical or fusiform. Receptacle pilose. — This 

 plant has been, we think, correctly referred by Hooker to Hymenoxys. 

 The two following species have precisely the same aspect, foliage, involucre, 

 &c., and can only be distinguished by the pappus. 



