SUNFLOWER FAMILY 141 
[Name Greek, meaning sharp, referring to the rigid, subulate-pointed divisions of the 
leaves. 
A monotypic genus of the southwestern United States. 
1. Oxytenia acerdésa Nutt. Oxytenia. Fig. 5206. 
Oxytenia acerosa Nutt. Journ. Acad. Phila. II]. 1: 172. 1848. 
Strigillose shrubby perennial 1-2 m. high, the stems conspicuously striate, greenish, leafy, 
erect branched above, sometimes leafless wl rush-like. Leaves petioled, 4 . long, pin- 
ly e€ i lobes sometimes wi 3 
similar lobes, the rachis, lobes, and usually the narrowly winged petiole all strongly revolute- 
margined, 0.5-1.5 mm. wide, the Lists. el since: heads 3-4 mm, thick, usually not nodding 
achenes 2 mm. long. 
Dry hei and along creeks, Sonoran Zones; southwestern Color o New Mexico, southern Utah, Nevada, 
orthern Arizona, and Inyo a California, in the Death Valley phe Pog Type locality: ‘Rocky Mountains, 
a Upper California.” July—Sep 
20. IVA L. Sp. Pl. 988. 1753. 
Annual or perennial herbs or shrubs, glabrous or pubescent, sometimes tomentose 
Leaves usually opposite at least below, linear to broadly ovate, entire, toothed, or dissected, 
sessile or petioled. Heads heterogamous, isciform, nodding, racemose, spicate, spi 
anicled, or scattered on the branches, sometimes ebracteate ; outer flowers (1-8 istillate. 
inner (3-20) perfect, ret corollas w ne . Involucre nearly hemispheric, usual 
double, the outer of 3-9 free or rarely connate, sometimes imbricated, mostly oval or 
ovate, subequal, subherbaceous phyllaries; the inner usually present, of f embranous 
phyllaries, opposite the outer phyllaries, each subtending d someti alf-enwrapping 
a pistillate flower, linear-spatulate to broadly obovate. ag va sm a basi imes n a 
jie parse i ft pistllae | flowers tubular or campanulate short, aimtiaes ‘tn cniecte. someti a 
4-5-toothed, in some species reduced to a fleshy ring or obsolete; corollas of perfect 
pari ‘oiniee centile or broadly funnelform from a aka base , 5-toothed. Fila- 
ents free or somewhat connate ; anthers lightly connate, at m maturity isjunct and usually 
pitt Be | with subentire to sagittate bases and inflexed terminal appendages. Style in the 
apex; of the disk rudim oie Pappus none. amed because of tts sim a Rpm in smell 
to Ajuga iva; the name of the latter derived from an old Latin word signifying an aborti- 
facient. 
A genus of about 15 species, all North American. Type species, Iva annua L. 
Heads racemose, mostly solitary in the axils of reduced leaves; inner phyllaries much narrower than the ovaries 
(and a sero 5 corolla of pistillate flowers evident, tubular, glandular; leaves obovate to linear, entire; 
plants peren 
Phyllaries —— at least to middle; herb, from running rootstocks. 1. I. axillaris. 
Phyllaries free; plant gen 2: is hee saa 
Heads scattered on the upper anches or spicate-panicled, mostly ebracteate; inner phyllarie 
der than 
ov: aries (and achenes) and infolding them on the edges; corolla of pistillate flowers ite or wlabrods. 
es serrate to bipinnatifid; plants annual. 
Plant 15 ot high or abs epic bipinnatifid, small; corolla of pistillate flowers tubular, ge ete below, vil- 
lou ensis. 
Plant up ‘ 2 ~ high; leaves sharply serrate, large; corolla of pistillate flowers short, toblgream campanlate, 
glabrou: 
1. Iva axillaris Pursh. Poverty Weed. Fig. 5207. 
Iva axillaris Pursh, Fl. Amer. Sept. 743. 1814 
va axillaris 8 robustior Hook. Fl. Bor. Amer. 1: .. = 
aris var. kebesten ens A, Gray in Torr. noe ing SS 17: 350. 1874. 
Perennial herb from ree rootstock: stems several, scattered, simple or simply branc ssi 
c , strigose, incurved- or rar rely s spreading- pubesc ent, somewhat glandular. Leave 
18-60 cm. hi s : 
opposite below, alternate whats obov ae to lance-elliptic, 1.54.5 cm. long, 4-15 mm. wide, obtu 
or acute, narrowed to the sessile or subsessile base, entire, thick, luce pubescent ii “ye the 
stem; heads nodding, 4-7 mm. thick, solitary in the axils of the ‘usually not much reduc 
leaves, Se scree involucre gamophyllous, shallowly or to middle about 5-lobed; Sistine 
flowers perfect, about 6-18; -signie sisneciensseic ar, 2-3 mm. long. 
ac troublesome weed, Transition and Sonoran Zones; Mani- 
toba iss os ali’ oum'to to southern pope: and Nevada, Utah, New Mexico, and Oklahoma. Type 
locality: “In Upper Louisiana.”” May—Sep 
