1606 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM 



Plants erect or ascending; pappus 1 to 1.8 mm. long. 



Heads several or numerous, cymose or cymose-panicled on a common peduncle. 



1. L. sinuatUB. 



Heads few or solitary, on long peduncles 2. L. pedunculatus. 



Plants procumbent; pappus usually less than 1 mm. long 3. L. filipes. 



1. Loxothysanus sinuatus (Less.) Robinson, Proc. Amer. Acad. 43: 43. 1907. 

 Bahia sinuata Less. Linnaea 5: 160. 1830. 



Bahia? nepetaefolia A. Gray, Proc. Amer. Acad. 5: 184. 1861. 



Tamaulipas, Puebla, and Veracruz; type from Hacienda de la Laguna, Veracruz. 



Low puberulous shrub; petioles 1 to 4.5 cm. long; leaf blades broadly ovate or 

 deltoid-ovate, 2.5 to 8 cm. long and wide, obtuse, coarsely repand or weakly 

 3-lobed, green above, griseous-puberulous or tomentulose beneath; heads about 

 7 mm. high, the pedicels 1.5 cm. long or less; longest palea of pappus 1.5 to 1.8 

 mm. long. 



2. Loxothysanus pedunculatus Rydb. N. Amer. Fl. 34: 33. 1914. 

 San Luis Potosf; type from Tamasopo Canyon. 



Similar to no. 1; heads less definitely cymose, the peduncles 2.5 to 7 cm. long; 

 pappus 1 to 1.2 mm. long. 



3. Loxothysanus filipes Robinson, Proc. Amer. Acad. 43: 44. 1907. 

 Veracruz; type from Zacuapan. 



Small and procumbent; leaf blades suborbicular, 1 to 2 cm. long, repand- 

 crenate; heads few; pappus 0.7 to 1.2 mm. long. 



99. DYSSODIA Cav. Descr. PI. 202. 1802. 



Reference: Rydb. N. Amer. Fl. 34: 160-179. 1915. 



Herbs or shrubs, with oil glands; leaves opposite or alternate, entire to dis- 

 sected; heads radiate or rarely discoid, yellow, rarely orange; involucre of usually 

 connate and ecjual, glandular-punctate phyllaries, often with a calyculus at base; 

 achenes slender; pappus of 5 to 20 paleae, these often aristate-dissected or awned. 



Leaves lanceolate to spatulate, serrate or entire, not lobed. 



Rays deep orange or brick-red 1. D. oaxacana. 



Rays j^ellow. 



Leaves lanceolate or lance-ovate, 1.2 to 2 cm. wide 2. D. serratifolia. 



Leaves narrowly lanceolate, 2 to 8 mm. wide 3. D. integrifolia. 



Leaves usually pinnatisect, if rarelj' entire then acerose-filiform. 



Involucre conspicuously calyculate by a series of outer phj'Uaries of different 

 form or texture from the inner. 

 Primary divisions of at least the lower leaves lanceolate to ovate. 

 Leaves opposite essentially throughout. 



Lateral lobes of the leaves distinctly stipitate, suborbicular, laciniate. 



4. D. speciosa. 

 Lateral lobes of the leaves subsessile, ovate, serrate-. 5. D. aurantia. 



Leaves chiefly alternate 6. D. porophylloides. 



Primary divisions of the leaves linear or essentially so. 



Pappus paleae dissected nearly to base into numerous bristles. 



Outer ph3ilaries linear-lanceolate, acuminate; peduncles usually thick- 

 ened under the heads; principal phyllaries essentially glabrous on 



back 7. D. tagetiflora. 



Outer phyllaries linear-spatulate or oblong, obtuse or acute; peduncles 

 scarcely or not thickened under the heads; principal phyllaries more 



or less densely hirsute on back 8. D. pinnata. 



Pappus paleae 1-aristate from a bifid apex or awnless_-10. D. treculii. 



