Baccharis thesioides
Baccharis bigelovii
Arizona baccharis, Mogollon baccharis
Bigelow's false willow
erect to ascending, slender, striate-angled, glabrous, scarcely resinous.
erect to ascending, slender, striate-angled, glabrous, resinous.
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; short-petiolate;
blades (1- or obscurely 3-nerved) obovate to oblanceolate, 20–35 × 3–15 mm, distally reduced and narrowed, bases cuneate, margins irregularly incised to coarsely serrate or 2-serrate, faces glabrous, gland-dotted, resinous.
campanulate;
staminate 3–6 mm, pistillate 3–6 mm.
campanulate;
staminate 4–5 mm, pistillate 4–5 mm.
30;
corollas 2.2–3 mm.
25–30;
corollas 2–2.6 mm.
20–30;
corollas 3 mm.
15–20;
corollas 3.5–4 mm.
lanceolate, 1–5 mm, margins scarious, erose-ciliate, medians green, apices acute or obtuse (erose, abaxial faces glabrous).
lanceolate, 1–4 mm, margins scarious, medians green, apices acute, erose.
(10–50+) in terminal, compact, rounded paniculiform arrays.
(20–50) in corymbiform arrays.
1.5–2.2 mm, 5-nerved, glabrous;
pappi 4–6 mm.
1.5–2.2 mm, 5-nerved, glabrous;
pappi 3–4.5 mm.
Baccharis thesioides
Baccharis bigelovii
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.)
Baccharis bigelovii occurs in the general Chihuahuan Desert region in the Davis Mountains of West Texas, and in the Chiricahua and Huachuca mountains of Arizona. It is recognized by the relatively short stature, obovate, coarsely and irregularly serrate leaves, erose-ciliate phyllaries, and 5-nerved cypselae. It is similar to B. thesioides, which differs mainly by having narrower, more oblong leaves with more evenly serrate margins and spinulose teeth. Further investigation may show these two taxa to be different geographic expressions of a single species centered in Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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