WOOTON AND STANDLEY — FLORA OF NEW MEXICO. 395 



Range: South Dakota and Pennsylvania to Utah and New Mexico. 



New Mexico: Santa Fe Creek; Pecos; Organ Mountains; Gila Hot Springs; White 

 Mountains; Hanover Mountain; Taos; Las Vegas; Sacramento Mountains. Dry lulls 

 and plains, in the Upper Sonoi-an Zone. 



2. TITHYMALUS Klotzsch & Garcke. 



Annual or perennial herbs, light green, glabrous, with erect stems umbellately 

 branching above; leaves alternate l)elow, the upper opposite, crowded, sessile, exstipu- 

 late, mostly entire; involucres sessile or pedunculate, in terminal cymes, the lobes often 

 toothed; glands 4, transversely oblong, reniform, or crescent-shaped by the hornlike 

 appendages, the missing one represented by a thin, often ciliate lobe; capsules ex- 

 serted, smooth or tuberculate; seeds variously pitted, sometimes carunciilate. 



KEY TO THE SPECIES. 



Capsules tuberculate. 



Stems cymosely branched below the umbel; capsules short- 

 warty 1. T. missouriensis. 



Stems racemosely branched; capsules long- warty. 



Leaves coarsely serrate; stems few 3. T. alius. 



Leaves obscurely serrulate; stems very numerous 2. T. mexicanus. 



Capsules smooth. 



Cauline leaves broadest above the middle 4. T. luridus. 



Ca\iline leaves broadest near the base. 



Seeds broadly truncate at the base; capsules 5 mm. long. 5. T. chamaesula. 

 Seeds roimded at the base; capsules 3 to 4 mm. long 6. T. montanus. 



1. Tithymalus missouriensis (Norton) Small, Fl. Southeast. U. S. 721. 1903. 

 Euphorbia arhansana missouriensis Norton, Rep. Mo. Bot. Gard. 11: 103. 1899. 

 Type locality: "In the Missouri River Valley, usually in open prairie or waste 



places, from Missouri to South Dakota and west to Colorado and Idaho, and extending 

 into eastern Washington." 



Range: As under type locality. 



New Mexico: Las Vegas; Farmington. Upper Sonoran Zone. 



2. Tithymalus mexicanus (Engelm.) Woot. & Standi. Contr. U. S. Nat. Herb. 16: 



145. 1913. 

 Euphorbia dictyosperma mexicana Engelm. in Torr. U. S. & Mex. Bound. Bot. 191. 



1859. 

 Euphorbia mexicana Norton, Rep. Mo. Bot. Gard. 11: 105. 1899. 

 Type locality: "Valley of the Nagas, Bolson de Mapimi," Mexico. 

 Range: Western Texas to southern Arizona and Mexico. 



We have seen no specimens of this from New Mexico, but Norton refers here one 

 collected by Thurber at Mule Spring (no. 282). 



3. Tithjnnalus altus (Norton) Woot. & Standi. Contr. U. S. Nat. Herb. 16: 145. 1913. 

 Euphorbia alia Norton, Rep. Mo. Bot. Gard. 11: 108. 1899. 



Type locality: "In the mountains of southern Arizona and New Mexico, and in 

 Mexico." 



Range: Arizona and New Mexico to Mexico. 



New Mexico: Mountains west of San Antonio; Mogollon Mountains; White Moun- 

 tains; Sacramento Moxmtains; Nutt. Transition Zone. 



4. Tithymalus luridus (Engehn.) Woot. & Standi. Contr. U. S. Nat. Herb. 16: 145. 



1913. 

 Euphorbia lurida Engelm. Proc. Amer. Acad. 5: 173. 1861. 

 Type locality: Base of the San Francisco Mountains, Arizona. 



