632 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Achenes turgid, ovoid or pear-shaped; bracts of the 
involucre alike, herbaceous................... 2. Iva (p. 633). 
Staminato and pistillate flowers in separate heads, the lat- 
ter 1 to 4, without corollas, inclosed in a nutlike or 
burlike involucre. 
Shrub; pistillate involucre with several scarious 
WINGS... ee eee cee cece cece eee eeee 3. HyMENOCLEA (p. 634), 
Herbs; pistillate involucre not winged. 
Involucres of staminate heads with distinct 
bracts; pistillate involucres large, with 
hooked spines..........2...0-2..2020-0eee 4, XantTurum (p. 634), 
Involucres of staminate heads with united bracts; 
pistillate involucres small, the spines not 
hooked, 
Spines or tubercles of the 1-flowered pistil- 
late heads in a single row............ 5, AMBROSIA (p. 635). 
Spines of the 1 to 4-flowered pistillate heads 
in more than one row..............--- 6. GAERTNERIA (p. 636), 
1. DICORIA Torr. & Gray. 
Low branched canescent annuals with alternate petiolate leaves; heads heteroga- 
mous, of 1 or 2 fertile and several staminate flowers; pistillate flowers without corollas; 
involucre of 5 short, oval or oblong, herbaceous bracts and 1 or 2 inner enlarged 
scarious ones; achenes flat on the inner surface, convex on the outer, with dentate or 
thin and scarious pectinate edges; pappus rudimentary, of several small scales, 
KEY TO THE SPECIES. 
Achenes 1 in each head; teeth of achenes conspicuous, often con- 
nected at the base... 2.2.2.2... cece cece cece eee nceeecceece 1, D, brandegei. 
Achenes 2 in each head; teeth of achenes inconspicuous, few, 
istinct..... 0... eee cee cece cece cee enecececceees 2, D. paniculata. 
1. Dicoria brandegei A. Gray, Proc. Amer. Acad. 11: 76. 1876. 
Tyre Locatiry: Along the San Juan, between McElmo and Recapture Creeks, 
Utah. 
RanGE: Colorado and Utah to northern Arizona and northwestern New Mexico. 
New Mexico: Shiprock (Standley 7188). Sandy soil in valleys, in the Upper So- 
noran Zone, 
2. Dicoria paniculata Eastw. Proc. Calif. Acad. IT. 6: 298. pl. 45. 1896. 
Type Locauity: Sandy flats along the San Juan River near the junction with 
McEImo Creek, Utah. 
RanGE: Southeastern Utah and northwestern New Mexico, 
New Mexico: Shiprock (Standley 71882), Sandhills in valleys, in the Upper So- 
noran Zone. 
The two species were growing together on sandbars along the San Juan at the Ship- 
rock Agency, and in the field were taken to be the same species. D. paniculata, as 
stated by Miss Eastwood, blooms earlier than D. brandegei, and the plants collected at 
Shiprock were in mature fruit and had lost many of their leaves, while those of the 
latter species were only flowering. 
