32 



NORTH AMERICAN FLORA 



[Volume 34 



Disk-corollas usually with slender glandular tube ; throat usually campanulate 

 or funnelform, not exceeding the tube in length, except in Platyschkuhria 

 and Htilsea. Achenes more or less distinctly angled, clavate-obpyramidal, 

 i. e., many times as long as broad and gradually tapering towards the base. 

 Pappus squamellate or rarely wanting. 



Achenes 4— 5-angled, or only the marginal ones 3-angled. 



Pappus present; lobes of the disk -corollas not longer than the throat. 

 Pappus oblique; squamellae at the exterior angles much shorter than 

 those at the interior ones ; heads discoid, with white flowers ; under- 

 shrubs. 

 Pappus not oblique; squamellae subequal. 



Involucre campanulate; outer bracts keeled; squamellae with 



distinct midrib; foliage conspicuously impressed-punctate. 

 Involucre hemispheric or broadly turbinate; bracts flat; herbage 

 not at all or inconspicuously punctate. 

 Corolla-throat campanulate; leaves more or less dissected. 

 Corolla-throat cylindro-campanulate, longer than the tube; 

 leaves entire, toothed, or merely lobed. 

 Involucral bracts in two subequal series but not imbricate ; 

 puberulent perennials with entire thick leaves and 

 woody caudices; pappus of 10—16 squamellae. 

 Involucral bracts in 2 or 3 series, somewhat imbricate, and 

 the outer somewhat shorter; fleshy villous or viscid 

 annuals or perennials; pappus of 4 squamellae. 

 Pappus wanting; lobes of the disk-corollas much longer than the short 

 funnelform throat. 

 Achenes all 3-angled. 

 Pappus wanting. 



Marginal achenes not winged. 



Marginal achenes with concave incurved wings on the inner two 

 angles. 

 Pappus present, of 8 squamellae. 



25. LOXOTHYSANUS. 



26. PlCRADENIOPSIS. 



27. Bahia. * 



29. Platyschkuhria. 



30. Hulsea. 



28. Amauriopsis. 



31. Vasquesia. 



32. Galeana. 



33. achyropappus. 



V 



25. LOXOTHYSANUS B. L> Robinson, Proc. Am. Acad. 43: 43. 



1907. 



Low shrubs or undershrubs. Leaves opposite, petioled, with ovate or orbicular blades, few- 

 lobed or crenate, canescent, at least beneath. Heads discoid. Involucres hemispheric or 

 turbinate; bracts subequal in 1-2 series, oblanceolate, puberulent, not scarious except slightly 

 so on the margins below. Receptacle small, plain. Flowers all hermaphrodite and fertile, 

 actinomorphic; corollas whitish; tube slender, glandular-puberulent, about equaling the cam- 

 panulate throat; limb 5-lobed. Anthers shortly sagittate at the base. Style-branches short 

 scarcely thickened below the apex and with obtuse appendices. Achenes 4-angled (described 

 as 5-angled), slender, attenuate at the base. Pappus oblique, of 5-8 oblong erose squamellae, 

 those of the exterior angle of the achenes much shorter than the inner ones. 



Type species, Bahia sinnata Less. 



Erect or ascending shrubs; involucre hemispheric, 5 mm. high. 



Inflorescence several-cephalous, corymbose with short individual peduncles. 1. L. sinuatus. 



Inflorescence 1-3-cephalous with long individual peduncles. 2. L. pedunculatus. 



Decumbent undershrub with slender branches; involucre turbinate, 4 mm. high. 3. L. filipes. 



1. Loxothysanus sinuatus (Less.) B. L> Robinson, Proc. Am. Acad. 



43: 43. 1907 



Bahia sinuala Less, in Schlecht. & Cham. Linnaea 5: 160. 1830. 

 Bahia nepelaefolia A. Gray, Proc. Am. Acad. 5: 184. 1861. 



A low shrub; stem terete, erect, tomentulose, corymbosely branched; leaves opposite, 



petioled; petioles 0.5-1.5 cm. long; blades deltoid-ovate or subcordate, 1-5 cm. long, sometimes 



3-lobed, or obtusely and coarsely toothed, puberulent above, grayish- or whitish-tomentulose 



beneath; heads corymbose; involucre hemispheric, 5 mm. high, 8-10 mm. broad; bracts 



about 12, oblanceolate, acute, tomentulose without; corollas white ; tube glandular-puberulent ; 



lobes lanceolate, fully as long as the turbinate-campanulate throat; achenes 3 mm. long, 



hirsute, attenuate at the base; inner squamellae about 1 mm. long, the outer ones half as long. 



Type locality: Hacienda de la Laguna, Vera Cruz. 

 Distribution: Tamaulipas, Puebla, and Vera Cruz. 



