Baccharis thesioides
Baccharis neglecta
Arizona baccharis, Mogollon baccharis
linear-leaf false willow, roosevelt or New Deal weed, rooseveltweed
erect to ascending, slender, striate-angled, glabrous, scarcely resinous.
(sometimes in clumps) erect, striate-angled, glabrous, eglandular.
usually present at flowering;
sessile;
blades (1-nerved) linear-oblanceolate to narrowly oblong, 20–40(–80) × 4–8 mm, bases cuneate, margins evenly serrate (teeth spinulose, apices acute, faces finely gland-dotted, not resinous).
present at flowering;
sessile;
blades (1-nerved, lateral veins obscure) narrowly elliptic to linear, 30–80 × 1–2(–5) mm (moderately thick), bases narrowly attenuate, margins entire or serrate with 2–3 small teeth, apices acute, faces glabrous, gland-dotted (distal reduced, entire).
campanulate; staminate 3–6 mm, pistillate 3–6 mm.
cylindro-campanulate; staminate 3.5–4 mm, pistillate 4–5 mm.
30;
corollas 2.2–3 mm.
15–30;
corollas 2.5–3.3 mm.
20–30;
corollas 3 mm.
10–15;
corollas 2.7–3.3 mm.
lanceolate, 1–5 mm, margins scarious, erose-ciliate, medians green, apices acute or obtuse (erose, abaxial faces glabrous).
ovate to lanceolate, 1–3 mm, margins yellowish, often scarious, medians green or reddish, apices acute to acuminate (often purplish, sometimes erose).
(10–50+) in terminal, compact, rounded paniculiform arrays.
(axillary and terminal on lateral branches) in pyramidal, paniculiform arrays.
1.5–2.2 mm, 5-nerved, glabrous;
pappi 4–6 mm.
1–1.5 mm, 10-nerved, glabrous;
pappi 7–12 mm.
Baccharis thesioides
Baccharis neglecta
Baccharis thesioides is recognized by its erect stems, narrow, oblong, evenly serrate leaves with finely spinulose teeth, heads in relatively small rounded arrays, and 5-ribbed cypselae with short pappi. It is sometimes confused with B. bigelovii, which has broader and irregularly serrate leaves. The two taxa may belong to the same species complex centered in Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
As circumscribed here, Baccharis neglecta is known north of Mexico only from central Texas, mostly on the Edwards Plateau. It is recognized by its tall and erect habit, very narrow leaves with small shallow teeth, pyramidal arrays, and 10-ribbed cypselae. It is most similar to B. salicina and may represent a xeromorphic, narrow-leaf form or variety of that species. Baccharis neglecta invades rangelands and pastures, forming dense stands. It is an especially aggressive invader of land converted from crops to pasture and it is a prolific seed producer; it readily resprouts when burned or cut.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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USDA Plants Database
