Baccharis thesioides

Kunth in A. von Humboldt et al.

in A. von Humboldt et al., Nov. Gen. Sp. 4(fol.): 48. 1818.

,

4(qto): 61. 1820.

Common names: Arizona baccharis
Synonyms: Baccharis alamosana S. F. Blake
Treatment appears in FNA Volume 20. Treatment on page 34. Mentioned on page 24, 26.

Shrubs, 100–200 cm (openly branched from bases). Stems erect to ascending, slender, striate-angled, glabrous, scarcely resinous. Leaves 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). Heads (10–50+) in terminal, compact, rounded paniculiform arrays. Involucres campanulate; staminate 3–6 mm, pistillate 3–6 mm. Phyllaries lanceolate, 1–5 mm, margins scarious, erose-ciliate, medians green, apices acute or obtuse (erose, abaxial faces glabrous). Staminate florets 20–30; corollas 3 mm. Pistillate florets 30; corollas 2.2–3 mm. Cypselae 1.5–2.2 mm, 5-nerved, glabrous; pappi 4–6 mm.


Phenology: Flowering Aug–Nov.
Habitat: Mountains and canyons, oak-pine forests
Elevation: 2200–2500 m

Discussion

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.

Selected References

None.

Lower Taxa

None.
... more about "Baccharis thesioides"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
spiciform +, racemiform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
Scott D. Sundberg† +  and David J. Bogler +
Kunth in A. von Humboldt et al. +
cuneate +
3-nerved +  and 1-nerved +
4 cm40 mm <br />0.04 m <br /> (8 cm80 mm <br />0.08 m <br />) +
2 cm20 mm <br />0.02 m <br /> (4 cm40 mm <br />0.04 m <br />) +
linear-oblanceolate;narrowly oblong +
4mm;8mm +
rugulose +  and muricate +
barbellulate +  and barbellate +
Arizona baccharis +
not 2-lipped +  and actinomorphic +
whitish +, white +  and pale-yellow +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
compressed +, obovoid +  and cylindric +
fertile +  and bisexual +
Ariz. +, N.Mex. +  and Mexico +
2200–2500 m +
resinous +
gland-dotted +
villous +, hispidulous +  and glabrous +
pistillate +  and staminate +
winged +  and beaked +
dispersed +
Mountains and canyons, oak-pine forests +
racemiform +, corymbiform +  and paniculiform +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
pistillate +  and staminate +
0.3 cm3 mm <br />0.003 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
campanulate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
spreading-reflexed;spreading-reflexed +
less deltate +  and lanceovate +
hispid +  and glabrous +
2-carpellate +
brownish +, whitish +  and tawny +
persistent +
25 +  and 50 +
0.4 cm4 mm <br />0.004 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Flowering Aug–Nov. +
lanceolate +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
in A. von Humboldt et al., Nov. Gen. Sp. +
1818 +  and 1820 +
styliferous +, neuter +  and pistillate +
bearing subulate enations +, hairy +  and bristly +
conic;tholiform;conic;tholiform;flat +
exalbuminous +
1 (?) +  and 20 (?) +
resinous +
erect +  and ascending +
striate-angled +
slender +
appendaged +  and truncate +
papillate +  and smooth +
Baccharis alamosana +
Baccharis thesioides +
Baccharis +
species +