STANDLEY TREES AND SHRUBS OF MEXICO 1547 



1. Helianthus niveus (Benth.) T. S. Brandeg. Proc. Calif. Acad. II 2: 173 



1889. 



Encelia nivea Benth. Bot. Voy. Sulph. 27. 1844. 



Helianthus tephrodes A. Gray in Torr. U. S. & Mex. Bound. Bot. 90. 1859. 



Viguiera nivea A. Gray, Proc. Amer. Acad. 8: 658. 1873. 



Viguiera tephrodes A. Gray, Proc. Amer. Acad. 17: 218. 1882. 



Gyrnnolomia encelioides A. Gray, Proc. Amer. Acad. 19: 4. 1883. 



Helianthus dealbatus A. Gray, Syn. FI. i^: 280. 1884. 



Viguiera sonorae Rose & Standi. Contr. U. S. Nat. Herb. 16: 20. pi. 16. 1912. 



Sonora and Baja California; type from San Quintin, Baja California. Cali- 

 fornia. 



Suffrutescent (sometimes annual?), decumbent at base, 30 to 60 cm. high, canes- 

 cent-strigillose; leaf blades ovate or lance-ovate to oblong, obtuse to acuminate, 

 cuneate to subcordate at base, slender-petioled, entire to serrulate, sometimes 

 greenish above; heads several, long-peduncled, about 2.5 cm. wide; disk purple; 

 pappus of several unequal deciduous awns and squamellae. 



2. Helianthus similis (T. S. Brandeg.) Blake, Contr. Grav Herb. n. ser. 54: 



189. 1918. 



Viguiera similis T. S. Brandeg. Zoe 5: 260. 1908. 



Cape Region of Baja California. 



Suffruticose, thinly tomentose, 1 meter high; leaf blades cordate, long-acu- 

 minate, sharply serrate; pappus of 2 awns and usually a few squamellae. (Descrip- 

 tion compiled.) 



64. PERYMENIUM Schrad. "Ind. Sem. Hort. Gotting. 1830;" Linnaea 6: 



Litt.-Ber. 73. 1831. 

 Reference: Robinson & Greenman, Proc. Amer. Acad. 34: 521-529. 1899. 

 Shrubs or herbs, usually strigillose or strigose; leaves opposite, usually ovate, 

 serrate, and petioled; heads radiate, yellow or the rays rarely white, solitary, 

 cymose, or panicled; involucre 2 to 4-seriate, the phyllaries usually indurate below 

 and with short herbaceous tips; receptacle paleaceous; rays pistillate; achenes 

 somewhat compressed, wingless or rarely winged; pappus of several to many 

 unequal or subequal setiform deciduous awns. 



Leaves green above, densely and canescently or subcanescently tomentose, 

 hispidulous, or strigillose beneath. 



Leaves narrowly linear, 1 to 4 mm. wide 28. P. stenophyllum. 



Leaves lanceolate to ovate. 



Heads larger, the disk in anthesis usually 1 cm. wide or more. 



38. P. nelsonii. 

 Heads smaller, the disk in anthesis much less than 1 cm. wide. 



Leaves lanceolate or lance-ovate, more than 3 times as long as wide. 



Phyllaries acute or acuminate; leaves densely hispidulous with spread- 

 ing hairs beneath, narrowed to an obtuse or obtusish tip. 



29. P. angustifolium. 

 Phyllaries obtuse or rounded; leaves densely strigillose or hispidulous 

 with subappressed hairs beneath, acuminate to a very acute tip. 

 Leaves turning blackish in drying; pedicels usually elongate. 



27. P. pellitum. 

 Leaves not blackening in drying; pedicels usually short. 



Leaves serrate or serrulate, not rugose above- .25. P. croceum. 

 Leaves subentire, strongly impressed-veined and rugose above. 



26. P. discolor. 



