Baccharis malibuensis |
Baccharis |
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Malibu baccharis, Malibu baccharis or coyote brush |
baccharis, false willow, groundsel-tree |
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Habit | Shrubs, 40–130(–210) cm (branched near bases). | Perennials, subshrubs, shrubs, or trees, 10–600 cm (dioecious [rarely monoecious], usually glabrous, often resinous; bases woody, rarely rhizomatous). | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | erect to arching, striate-angled, glabrous or sparsely villous distally (hairs short, spreading). |
(1–20+) usually erect or ascending, rarely prostrate (usually striate-angled, rarely terete and smooth; usually green), glabrous, glabrate, hispidulous, or villous, often resinous. |
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Leaves | present at flowering (sparse); short-petiolate; blades (1- or 3-nerved) linear to linear-oblanceolate, (15–)20–45(–65) × 1–4(–5) mm, bases narrowly attenuate, margins entire or weakly serrate, apices acute or acuminate (crustose); faces glabrous or sometimes sparsely pilose (hairs 2-seriate), adaxial gland-dotted (in pits; distal leaves reduced, crowded). |
cauline (sometimes withering and sparse or absent at flowering); alternate; sessile or petiolate; blades 1- or 3-nerved, linear, lanceolate, ovate, oblong, obovate, or rhombic (usually reduced distally), margins entire or coarsely serrate, faces usually glabrous, rarely hispidulous or villous, often gland-dotted and resinous. |
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Involucres | turbinate; staminate ca. 5 mm, pistillate ca. 5 mm. |
cylindric to campanulate or hemispheric, 3–9 mm diam. |
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Receptacles | flat, tholiform, or conic, pitted or smooth (glabrous, tomentose, or glandular), usually epaleate. |
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Pistillate florets | 35–38; corollas 2.2–4.2 mm. |
20–150; corollas whitish, filiform-tubular, lobes 5, spreading-reflexed, ± deltate to lance-ovate; style branches (glabrate, flattened), appendages lacking. |
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Staminate florets | 23–36; corollas 3.7–4.5 mm. |
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Phyllaries | linear-lanceolate, 2–5 mm, margins yellowish white, scarious, medians green, apices becoming brown with age, ciliate distally. |
20–40 in 2–5 series (mid usually green, sometimes red or purple), 1-nerved, ovate to lanceolate, unequal, margins usually scarious, often erose or ciliate, sometimes keeled (midribs evident or not, apices obtuse to acute or acuminate, sometimes keeled), usually glabrous, rarely hispid. |
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Heads | in cylindric paniculiform arrays. |
(sessile or pedicellate, unisexual) discoid, usually in paniculiform or corymbiform, sometimes racemiform arrays or borne singly. |
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Cypselae | 2.4–3 mm, 5-nerved, faces with thick, irregular, glandlike hairs; pappi 6.5–7.5 mm. |
light brown, obovoid to cylindric, ± compressed, 5–10-nerved, glabrous or hispid; pappi persistent or falling, of 25–50 whitish to tawny, rarely brownish (elongating and usually surpassing phyllaries in fruit), minutely barbellate, apically attenuate bristles in 1–3 series. |
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Functionally | staminate florets 10–50; corollas white to pale yellow, tubes about equal to narrowly funnelform throats, lobes 5, spreading-reflexed, deltate to lance-ovate (pappi of 20–40 equal, often crisped and minutely barbellate or distally plumose bristles). |
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x | = 9. |
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Baccharis malibuensis |
Baccharis |
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Phenology | Flowering Aug–Sep. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Grassy openings, chaparral | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 100–300 m (300–1000 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
CA |
Mostly New World tropics and warm-temperate regions; especially diverse in South America |
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Discussion | Of conservation concern. Baccharis malibuensis is known only from the Malibu Creek drainage area in the Santa Monica Mountains (Los Angeles County). It is distinguished by its narrow, often conduplicate and glabrate leaves, cylindric arrays, and summer flowering. According to Beauchamp and Henrickson, it appears to be closely related to and possibly derived from B. plummerae, from which it differs primarily in leaf size, teeth, and indument. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 350–450 (21 in the flora). Baccharis comprises mostly dioecious shrubs with gland-dotted leaves and is sister to the polygamo-dioecious genera Archibaccharis and Heterothalamus. Sections have been delimited within Baccharis (e.g., D. A. Giuliano 2001; Giuliano and G. L. Nesom 2003; Nesom 1990h, 1998). Species of Baccharis often occur in wet sites such as stream banks, washes, ditches, and marshes. Useful taxonomic characters include habit, branching structure, leaf shape, size, margins, and vestiture, arrangement of heads, and number of nerves on cypselae. Collectors should try to collect both staminate and pistillate individuals to facilitate identification. Hybridization and introgression have been found between Baccharis halimifolia and B. neglecta, and between B. halimifolia and B. angustifolia. Intermediates between B. thesioides and B. bigelovii have been collected in southern Arizona. Baccharis is of little economic importance, except for species that are invasive or toxic to livestock (P. E. Boldt 1989). Baccharis is not generally palatable to cattle; it could become the only forage available as a result of overgrazing. In the southwestern United States, B. pteronioides is a hazard to cattle; B. halimifolia, B. angustifolia, and B. glomeruliflora cause similar problems in the eastern United States (G. E. Burrows and R. J. Tyrl 2001). Baccharis pilularis invades overgrazed or eroded rangelands in California and Oregon. Baccharis halimifolia has been introduced in Australia, infesting large areas along the eastern coast, prompting the search for biological control agents (Boldt). Neomolina F. H. Hellwig is an illegitimate, later homonym that has been applied to species included here in Baccharis. In key leads, references to pappi are to pappi on cypselae (i.e., in pistillate heads). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 29. | FNA vol. 20, p. 23. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Name authority | R. M. Beauchamp & Henrickson: Aliso 14: 202, fig. 3. (1996) | Linnaeus: Sp. Pl. 2: 860. (1753): Gen. Pl. ed. 5, 370. (1754) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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