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mule's fat, mule-fat, seepwillow, water wally

desert baccharis, squaw false willow

Habit Shrubs, 30–400 cm (stems clustered). Shrubs, 50–200 cm (freely branched, broomlike).
Stems

spreading to ascending, green to tan, simple proximally, sparingly branched distally, striate-angled, glabrous or minutely hairy, resinous and ± resin-varnished.

erect, fastigiate, striate-angular, green, glabrous, resinous.

Leaves

present at flowering (abundant, well developed);

sessile or petiolate;

blades lanceolate-elliptic, slightly falcate (willowlike), 30–150 × 3–20 mm, bases attenuate, margins usually finely serrate from bases to apices, sometimes entire, apices acute to acuminate, faces glabrous, gland-dotted, ± resinous.

cauline (proximal withering and sparse by flowering);

sessile;

blades (1-nerved) broadly oblanceolate to obovate or spatulate, 10–35 × 5–15 mm (thick, firm), bases attenuate, margins entire or irregularly serrate (teeth 1–4, distal leaves entire), apices obtuse to acute, faces glabrous, gland-dotted, resinous.

Involucres

hemispheric;

staminate 3–6 mm, pistillate involucres 3–6 mm.

funnelform to campanulate;

staminate 3–5 mm, pistillate 3–5 mm.

Pistillate florets

50–150;

corollas 2–3.5 mm.

15–30;

corollas 1.6–2.7 mm.

Staminate florets

(10–)17–48;

corollas 4–6 mm.

24–33;

corollas 2–3.5 mm.

Phyllaries

ovate to lanceolate, 2–4 mm, margins scarious, erose or irregularly dentate, midribs distinct, medians green or reddish, apices (greenish or brownish purple) obtuse to acuminate (pale and dry, glabrous).

ovate to linear-lanceolate, 1–5 mm, margins scarious, erose, medians green, apices rounded to acute, glabrous, gland-dotted, resinous.

Heads

in terminal, compound corymbiform arrays (often involving distal branches).

(sessile or short-pedunculate on lateral branches) in crowded paniculiform arrays.

Cypselae

0.8–1.5 mm, 5-nerved, glabrous;

pappi 3–6 mm.

1–2 mm, prominently 10-nerved, glabrous;

pappi 1.7–3.1 mm.

2n

= 18, 36.

= 18.

Baccharis salicifolia

Baccharis sergiloides

Phenology Flowering (Jan–)Mar–Oct. Flowering Jul–Oct.
Habitat Stream banks, dry washes, sandy flood plains, riparian woodlands, disturbed sites, ditches Gravelly or sandy streambeds, dry washes, grasslands
Elevation 30–2400 m (100–7900 ft) 100–1800 m (300–5900 ft)
Distribution
from FNA
AZ; CA; CO; NM; NV; TX; UT; Mexico; South America
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Baccharis salicifolia is part of a complex that extends through the southwestern United States, Mexico, Central America, and South America to Argentina and Chile (J. Cuatrecasas 1968). It is recognized by the narrowly lanceolate, willowlike, finely serrate leaves with acute or acuminate apices, smallish heads in dense clusters, reddish phyllaries, and 5-nerved cypselae. By tagging and measuring individual plants throughout the year, D. H. Wilken (1972) demonstrated that B. salicifolia has distinct seasonal forms. The North American plants were once known as B. glutinosa or B. viminea, which were differentiated from each other by differences in woodiness, leaf size and serration, and flowering time.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Baccharis sergiloides is recognized by its fastigiate, broomlike habit, and large obovate leaves that often wither before flowering. It differs from B. sarothroides in its larger leaves, more or less sessile and lateral heads, and smaller florets and fruits.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 20, p. 31. FNA vol. 20, p. 33.
Parent taxa Asteraceae > tribe Astereae > Baccharis Asteraceae > tribe Astereae > Baccharis
Sibling taxa
B. angustifolia, B. bigelovii, B. brachyphylla, B. dioica, B. glomeruliflora, B. glutinosa, B. halimifolia, B. havardii, B. malibuensis, B. neglecta, B. pilularis, B. plummerae, B. pteronioides, B. salicina, B. sarothroides, B. sergiloides, B. texana, B. thesioides, B. vanessae, B. wrightii
B. angustifolia, B. bigelovii, B. brachyphylla, B. dioica, B. glomeruliflora, B. glutinosa, B. halimifolia, B. havardii, B. malibuensis, B. neglecta, B. pilularis, B. plummerae, B. pteronioides, B. salicifolia, B. salicina, B. sarothroides, B. texana, B. thesioides, B. vanessae, B. wrightii
Synonyms Molina salicifolia, B. viminea, B. viminea var. atwoodii
Name authority (Ruiz & Pavón) Persoon: Syn. Pl. 2: 425. (1807) A. Gray: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 83. (1859)
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