140 COMPOSITAE 
18. SANVITALIA Lam. Journ. Hist. Nat. 2: 176. pl. 33. 1792. 
Simple or branching, annual or perennial herbs. Leaves opposite, entire, petioled or 
sessile. Heads heterogamous, radiate, terminal on the branches or sessile in the upper 
to narrowly conical, the receptacular bracts scarious and rather firm, ge ser inet and 
an e 
pappus oo or of 1-2 slender awns or teeth. [Name in honor of a noble Italian family, 
Sanvita 
Ses ge my of about 4 species, natives of southwestern United States and Mexico. Type species, Sanvitalia pro- 
cumbens 
1. Sanvitalia abértii A. Gray. Abert’s Sanvitalia. Fig. 5205. 
Sanvitalia abertit A. Gray, Mem. Amer. Acad. II. 4: 87. 1849. 
annual from a taproot, 1-3 dm. high, simple or with ascending opposite branches, the 
stems hispidulo us Lice curved asce tice hairs, usually becoming glabrate. Leaves linear- lanceolate 
to lanceolate, short: than the internodes, the petioles 2-12 mm. long, the blades 2.5-5 cm. long, 
cuneate at base and somewhat decurrent on the vietiole, the lea if “margins and captes ces hispiduus 
with pustulate-based hairs ; be ‘age ubequal in 2 series; receptacle narrowly cal to 
nearly subulate, the receptacular bracts much be pin ssing the disk- flowers; diner “6-10, the 
mm. long, emar a glee lobed) and many-veined ; disk-flowers about 1.5 mm. long, 
long, 
4-angled, the angles often compressed and w — — conspicuously and irregularly warty, ‘black- 
ish me sometimes se ith a chalky wat ates epappo 
rid mesas and s Sonoran = in Sah ies x Clark Mountain, eastern San Bernardino poy 
(Root 4954, 4893), ea py cng in northern and central Arizo oe Pasa also Chihuahua and Sonora. Type 
v2 “between Bent’s Fort and Santa 6,” New Mexico. pores 
Subtribe AMBROSIINAE 
Heads heterogamous (a few unisexual staminate heads present on inflorescence of Dicoria); pistillate flowers and 
achenes not ccs sagpe in a bur-like or nut-like involucre. 
eee more or jee urgid, whee “ead phyllaries in 1 or 2 series, the inner when present not noticeably larger 
and not min: a accresce 
Anew densely wRous; rahe their lobes linear-filifor 19. rages 
villous; a entire, lobed, or wea se cleft. 20. 
scale ae and wit pectinate or toothed wings; inner phyllaries larger than the a) Eeakine ac- 
tcoria 
Heads unisexual, ek staminate borne above the pistillate; pistillate flowers and achenes in a nut-like or bar-like 
volucr 
Phyllaries ofthe the staminate heads united; fruiting involucres winged, tuberculate, or if hooked spines present 
Fruiting ede with conspicuous transverse wings; leaf divisi leaves linear-filif 
22. Hymenoclea. 
Fruiting involucres without transverse wings; leaves toothed or pinnatifid, the lobes not linear-filiform. 
ruiting involucres unarmed or with a single row of tubercles or teeth. 23. Ambrosia. 
Fruiting involucres with several spines in more than 1 row. 24. Franseria, 
Phyllaries of the staminate heads free; fruiting involucres conspicuously covered with hooked spines or 
prickles. 25. Xanthium. 
19. OXYTENIA Nutt. Journ. Acad. Phila. II. 1: 172. 1848. 
Strigillose perennial, shrubby and pth f with striate stems. Leaves alternate, 
petioled, pinnately divided nearly to midrib or the upper entire, the divisions linear -fili- 
form, revolute-margined. Heads eae aang disciform, numerous, spicate-panicled 
i 
t 
of the pistillate flowers reduced to a thick fleshy ring, of the perfect ones funnelform, 
5-toothed, Saeed and as pilose above. Filaments free; anthers lightly 
te, at isj 
wers un , at apex slightly dilated and Achenes obovoid, convex 
dorsally, flattish, pecteali: l-ridged on each face, “ oc aes pappus none. 
