Hymenatherum. COMPOSITE. 3g'7 



167. HYMENATHfiRCJM, Cass. ('Y/.^., membrane, iO^p, awn, the 

 palea: of the pappus anned.) — Low herbs or suffruticulose plants (chiefly of the 

 Mexican borders), of various habit, mostly pleasant-scented ; with alternate or 

 opposite leaves, and small or barely middle-sized u,uallv radiate heads of vellow 

 flowers. — Cass. Bull. Philom. I.si7, ISls. & Diet. xxii. 313; Gray, PI. Fendl. 

 ys, >& ri. Wright, i. 11.5; Benth. ct Hook. Gen. li. 410. Hymenatherum (excl. 

 § i). Dysodla § Adphyllcea, i Gnaphallopsis, DC. Prodr. Now adding Thy- 

 mophylla. Lag. (sliglitly earlier published name, but obscure), & Xoire///«,°Gray, 

 with muticous pappus. Mde Proc. Am. Acad. xix. 40. 



§ 1. AciPHYLL.i;A, Gray. Palea3 of the simple pappus numerous (18 to 20), 

 above resolved into about 5 or the alternate ones into 3 capillary bristles, like 

 those of Dysodla (to which it makes transition) : heads sessile or nearly so at the 

 end of the woody branchlets : leaves entire, opposite. — PI. Wright, i. 115. 



— H. acerosuin, Gray, 1. u. shrubby, a span to a foot high from a thick base, rigid, exceed- 

 ingly branched : branches barely puberulent : leaves filiform-acerose, usually with sliurter 

 cues fascicled in must of the axils : heads 3 or 4 lines high : involucre with copious large 

 oil-glands, subtended by uppermost pair of leaves or by a feiv shorter subulate foliaceous 

 bracts: rays oblong. — Dijsudiat (Ariphi/Uaa) acerosa, DC. Prodr. v. 641. Ji /;./-. ///rca 

 acerosa, (.iray, PI. Fendl. 91. — W. borders of Texas to Arizona toward the ilexican boun- 

 dary, Wright, &c. (Mex.) 



§ 2. Dysodiopsis. Gray, 1. c, excl. spec. Paleie of the simple pappus only 

 10, rigid, not longer than the thickish akene, much shorter than disk-corolla, 

 some entire with a single awn, others with 3 aristate-subulate tips : beads looselv 

 foliose-calyculate : leaves alternate. 



N H. tagetoides. Gray, 1. c. A rigid aunual, and becoming perennial, glabrous, a foot or so 

 high, fastigiately branched at summit : leaves narrowly linear, 2 or 3 inches lung, rigid, 

 laciniately and spinulosely dentate or almost pinnatifid: heads indistinctly peduncled, less 

 than half-inch bigh : involucre rigid ; its bracts obviously imbricated, but connate almost to 

 the tip: rays oblong, conspicuous. — -D^/sorfm tagetoides, Torr. & Gray, Fl. ii. 361. — Low 

 prairies, Texas ; first coU. by iJrummond. 



§ 3. EcHTMENATHEKUM. Gray. 1. Gi'''"Pale8B of the pappus 10 to 20. all or 



the inner ones l--j-aristate. and the awns about equalling or surpassing the 'li^k- 



corolla : heads naked at base, or with some small and scanty subulate accessor}- 



bracts. (See also § 4.) 



* Eavs inconspicuous and few, with li^ule not surpassing the disk or the double and dimorphous 

 pappus ; this of 10 rigid paleae in each series, inner with stout awns. 



H. Neo-Mexicanum, Gray, a slender erect annual, a foot or less high, glabrous, fas- 

 tigiatelv branched ab<jve : leaves mostly pinnately parted into a few linear-filiform entire 

 divisions : lower opposite, upper alternate : heads short-peduncled : involucre turbinate, 3 or 

 4 lines hish, of .5 to 7 oblong connate bracts, subtended by 2 to 4 filiform-subulate bractlets : 

 akenes appressed-villous at the attenuate base, shorter than the inner i>appus, the oblong- 

 lanceolate palete of which aje cleft into 3 scabrous rigid awns, the middle one longer; tlm.-e 

 of the short outer pappus oblong>patulate, retuse. — Proc. Am. Acad. xix. 40. Adinoj^hi/Uum 

 Wrightii, Gray, PI. Wright, ii. 92. — Hillsides, New Jlexico, Wright. 



# * Rays exserled and conspicuous, oblong: awns of the pappus capillary or slender-setiform. 

 H— Most of the paleae of the nearly homomorphoiis pappus 3-awned, lateral a^^^ls shorter: glabrous 

 leaf v-stenimed lierbs, either annuals or slender-rooted subperennials : upper leaves all alternate. 



g_ polychi^ttim, Gray. Luw, diffusely much branched from an annual root, leafy to 

 near the numerous short-peduncled iieads: leaves not rigid, pinnately parted into several 

 short^filiform obtuse and pointless divisions; involucre barely 3 lines high, 10-16-toothed : 



