WOOTON AND STANDLEY—FLORA OF NEW MEXICO. 395 
Rance: 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 hills 
and plains, in the Upper Sonoran Zone. 
2. TITHYMALUS Klotzsch & Garcke. 
Annual or perennial herbs, light green, glabrous, with erect stems umbellately 
branching above; leaves alternate below, 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 carunculate. 
KEY TO THE SPECIES. 
Capsules tuberculate. 
Stems cymosely branched below the umbel; capsules short- 
C0 1. T. missouriensis. 
Stems racemosely branched; capsules long-warty. 
Leaves coarsely serrate; stems few..................-- 3. T. altus. 
Leaves obscurely serrulate; stems very numerous. ..... 2. T. mexicanus. 
Capsules smooth. 
Cauline leaves broadest above the middle.................- 4. T. luridus. 
Cauline leaves broadest near the base. 
Seeds broadly truncate at the base; capsules 5 mm. long. 5. 7. chamaesula. 
Seeds rounded at the base; capsules 3 to 4 mm. long.... 6. T. montanus. 
1. Tithymalus missouriensis (Norton) Small, Fl. Southeast. U. 8. 721. 1903. 
Euphorbia arkansana missouriensis Norton, Rep. Mo. Bot. Gard. 11: 103. 1899. 
Type Locauity: ‘‘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.” 
Rance: As under type locality. 
New Mexico: Las Vegas; Farmington. Upper Sonoran Zone. 
2. Tithymalus mexicanus (Engelm.) Woot. & Stand1. Contr. U. 8. Nat. Herb. 16: 
145. 1918. 
Euphorbia dictyosperma mexicana Engelm. in Torr. U. 8. & Mex. Bound. Bot. 191. 
1859. 
Euphorbia mexicana Norton, Rep. Mo. Bot. Gard. 11: 105. 1899. 
Typr Locauity: ‘‘Valley of the Nagas, Bolson de Mapimi,”’ Mexico. 
Rance: 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. Tithymalus altus (Norton) Woot. & Standl. Contr. U. 8. Nat. Herb. 16: 145. 1913. 
Euphorbia alta Norton, Rep. Mo. Bot. Gard. 11: 108. 1899. 
Tyer Locality: ‘‘In the mountains of southern Arizona and New Mexico, and in 
Mexico.” 
Rance: Arizona and New Mexico to Mexico. 
New Mexico: Mountains west of San Antonio; Mogollon Mountains; White Moun- 
tains; Sacramento Mountains; Nutt. Transition Zone. 
4, Tithymalus luridus (Engelm.) Woot. & Standl. Contr. U. 8. Nat. Herb. 16: 145. 
1913. 
Euphorbia lurida Engelm. Proc. Amer. Acad. 5: 173. 1861. 
Tyrer Locality: Base of the San Francisco Mountains, Arizona. 
