250 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



6. Ruprechtia pallida Standi., sp. nov. 



MichoaoSn and Guerrero; type from Cayaco, Michoaean (Nelson 6964; U. S. 

 Nat. Herb. no. 399283). 



Branches blackish brown, rugose ; ocreae 1.5 mm. long ; i>etioles 3 to 5 mm. 

 long; leaf blades oblanceolate-oblong or elliptic-oblong, 4.5 to 7 cm. long, i;5 to 

 2 cm. wide, usually cuneate at base, obtuse to subacute at apex, subcoriaceous, 

 pale on both surfaces, glabrous above, the venation inconspicuous, glabrous 

 beneath except for a few scattered hairs along the costa, tlie lateral veins about 

 9 on each side, prominent, the other venation inconspicuous ; pistillate racemes 

 (very immature) about 2 cm. long, densely flowered; calyx densely pilose with 

 short subappressed hairs. 



32. CHENOPODIACEAE. Goosefoot Family. 



Refeeence: Standley, Chenopodiaceae, N. Amer. Fl. 21: 3-93. 1916. 



Shrubs, usually low, often succulent ; leaves opposite or alternate, estipulate, 

 sometimes reduced to scales; flowers small, perfect or unisexual; fruit a 

 utricle, 1-seeded. 



A large number of herbaceous species of various genera are found in Mexico. 



Leaves reduced to scales ; stems jointed ; flowers in fleshy spikes or sunk in the 

 joints of the stems. 

 Branches alternate 3. ALLENROLFEA. 



Branches opposite 4. ARTHROCNEMUM. 



Leaves well developed ; stems not jointed ; flowers solitary or clustered in the 

 axils of the leaves. 

 Embryo spirally coiled ; leaves very fleshy, terete or semiterete__5. DONDIA. 

 Embryo not coiled ; leaves usually flat. 

 Pubescence of inflated hairs or wanting, never of slender hairs. 



1. ATRIPLEX. 

 Pubescence of silky hairs 2. EUROTIA. 



1. ATRIPLEX L. Sp. P'l. 1052. 1753. 

 Shrubs with scurfy whitish pubescence ; leaves alternate or opposite, entire or 

 dentate ; flowers unisexual ; fruit inclosed by bracts. • 



Several herbaceous representatives of the genus are found in Mexico. The 

 plants are of considerable value as forage for stock. _ 



Fruiting bracts with 4 longitudinal wings. 



Bracts 7 to 25 mm. long, the free portion equaling or usually shorter than the 



wings 1. A. canescens. 



Bracts 4 to 10 nun. long, the free portion much longer than the wings. 

 Pedicels of the fertile flowei"S 2 nun. long or less; l)racts 4 to 6 mm. long. 



2. A. linearis. 



Pedicels 4 to 7 mm. long; bracts G to 10 mm. long 3. A. macropoda. 



Fruiting bracts not winged. 



Leaves all or nearly all opposite. Leaves sessile, 2 to 5 mm. long. 



4. A. inataniorensis. 

 Leaves alternate, or the lowest opposite. 



Leaves dentate 5. A. acanthocarpa. 



Leaves entire.- 



Leaves sagittate, clasping, 2 to 4 nun. long 6. A. julacea. 



Leaves never sagittate, usually nmch larger. 



Bracts entire, 5 to 12 nun. long 7. A. confertifolia. 



Bracts dentate or crenulate, usually smaller. 



