402 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
KEY TO THE SPECIES. 
Plants hirsute............22.-. 0-22 00 220 eee eee ee eee ee 1. D. neomericana., 
Plants glabrous. , 
Stems slender, much branched; leaves petiolate............ 2. D. laevis. 
Stems stout, simple; leaves sessile......................... 3. D. cyanophylia. 
1. Ditaxis neomexicana (Muell. Arg.) Heller, Cat. N. Amer. Pl. 5. 1898. 
Argyrothamnia neomexicana Muell. Arg. Linnaea 34: 19. 1865. 
Type Locauity: ‘‘In Novo-Mexico.’’ The types are Wright’s 643 and 1797. The 
first of these is certainly Texan, but the second may have come from New Mexico. 
Rance: Western Texas to Arizona and adjacent Mexico, 
New Mexico: South of Hillsboro ( Metcalfe 1287). 
2. Ditaxis laevis (Torr.) Heller, Cat. N. Amer. Pl. 5. 1898. 
Aphora laevis Torr. U. 8. & Mex. Bound. Bot. 196. 1859. 
Argyrothamnia laevis Muell. Arg. Linnaea 34: 147. 1865. 
TYPE LOCALITY: Western Texas. 
Ranae: Western Texas and southern New Mexican. 
New Mexico: Roswell and vicinity. Dry plains, in the Lower Sonoran Zone. 
3. Ditaxis cyanophylla Woot. & Standl. Bull. Torrey Club 86: 106. 1909. 
Tyre Locauiry: Kingston, Sierra County, New Mexico. Type collected by 
Metcalfe, May 25, 1904. 
Rance: Western New Mexico and adjacent Arizona. 
New Mexico: Kingston; south of Rito Quemado. 
11. CROTON L. 
Herbaceous or woody annuals or perennials, more or less stellate-pubescent, with 
alternate simple entire leaves and inconspicuous monecious or dicecious flowers, 
these in axillary or terminal, spicate or racemose clusters, sometimes crowded; stami- 
nate flowers uppermost; sepals 4 to 6, usually 5; petals mostly present but small, 
alternating with glands; stamens 5 or more; pistillate flowers usually loosely clustered; 
their sepals 5 to 10, the petals usually wanting; stigmas much divided; capsule 
3-celled, splitting into 2-valved carpels each containing 1 seed. 
KEY TO THE SPECIES 
Annuals. 
Plants stellate-pubescent throughout, grayish.............. 1. C. texensis. 
Plants glabrous, bright yellowish green.................... 2. C. luteovirens. 
Perennials. 
Low shrub with cordate or subcordate leaves.............. 3. C. fruticulosus. 
Herbs, sometimes suffrutescent near the base, the leaves 
never cordate, mostly oval or oblong, rounded at the 
base. 
Staminate flowers petaliferous. 
Leaves gray on both surfaces, the upper ones obtuse. 4. C. corymbulosus. 
Leaves green above, the upper ones acute......... 5. C. eremophilus. 
Staminate flowers apetalous. 
Plants loosely stellate-pubescent, not silvery...... 6. C. tenuis. 
Plants densely lepidote-stellate, silvery........... 7. C. neomexicanus. 
1. Croton texensis (Klotzsch) Muell. Arg. in DC. Prodr. 152: 692. 1866. 
Hendecandra texensis Klotzsch in Wiegmann, Archiv Naturg. ‘7: 252. 1841. 
Hendecandra multiflora Torr. in Frém. Rep. Exped. Rocky Mount. 96. 1845. 
TYPE LocALITy: Texas. 
Rance: Wyoming and Illinois to Arizona and Texas, south into Mexico. 
