Xylorhiza glabriuscula
Xylorhiza
common woody aster, smooth woody-aster
desert-aster, woody-aster
branched mostly in proximal 3/4 (leafy 2/3+ their lengths), villoso-puberulent or glabrous, eglandular.
(often white-barked) erect, branched, glabrous or villous to tomentose, sometimes stipitate-glandular.
blades oblanceolate, 2.5–8 mm wide, bases attenuate, not clasping, margins flat, entire, faces villoso-puberulent or glabrous, eglandular.
cauline; alternate;
sessile or subpetiolate;
blades mostly 1-nerved, linear to lanceolate or oblanceolate, oblong, or narrowly elliptic, margins entire or dentate-spinulose (apices acute), faces glabrous or sparsely tomentose to villous, sometimes stipitate-glandular.
2–6 cm.
7–14 × 12–25 mm.
campanulate to hemispheric, 7–20 × 12–40(–48) mm.
flat, pitted, epaleate.
-branch appendages equal or shorter than stigmatic lines.
12–25;
corollas white.
(4–)12–60(–85), pistillate, fertile;
corollas white to light blue or purple (coiling at maturity).
30–140, bisexual, fertile;
corollas yellowish, tubes slightly shorter to longer than narrowly funnelform throats, lobes 5, spreading, triangular;
style-branch appendages lanceolate.
25–45 in 3–6 series, 1-nerved (keeled), narrowly lanceolate, unequal, proximally white-indurate, margins scarious (apices green, erect or spreading), abaxial faces glabrous or sparsely tomentose to villous, sometimes stipitate-glandular.
radiate, borne singly (terminal on ebracteate peduncles).
(brownish) fusiform to linear or ovoid, ± compressed to subterete, 4-ribbed, faces sericeous (hairs subappressed, long, silky);
pappi persistent, of 30–45 tawny, stout, unequal, often flattened, barbellate, apically attenuate bristles in 2–3 series.
= 6.
= 12.
Xylorhiza glabriuscula
Xylorhiza
Species 10 (9 in the flora).
Xylorhiza species were considered by A. Cronquist and D. D. Keck (1957) to be primitive members of the genus Machaeranthera, where they were recently maintained (Cronquist 1994). T. J. Watson (1977) and other contemporary botanists, however, have recognized Xylorhiza as a distinct genus characterized by the following features: perennial herbs, subshrubs, and shrubs from large, woody taproots with woody, branched, persistent caudices; large, single heads; long phyllaries with erect or spreading apices; white or bluish rays; large cypselae; and vernal flowering. The base chromosome number of Xylorhiza (x = 6) also contrasts with that of Machaeranthera (x = 4 or 5). Two sections were recognized by Watson: sect. Xylorhiza (subshrubs or perennial herbs) and sect. Californica T. J. Watson (shrubs, including X. cognata, X. orcuttii, and the Mexican endemic X. frutescens).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaf margins (many of them) toothed | → 2 |
1. Leaf margins all or nearly all entire | → 5 |
2. Leaf blades mostly 1–2.5 mm wide, margins involute | X. confertifolia |
2. Leaf blades mostly (2–)2.5–15 mm wide, margins flat | → 3 |
3. Leaf blades linear-oblong to linear-lanceolate, bases truncate or rounded-auriculate | X. linearifolia |
3. Leaf blades oblanceolate to oblong-spatulate, bases tapering | → 4 |
4. Stems leafy for 2/3 + their lengths; peduncles 2–6 cm; involucres 7–14 × 12–25 mm | X. glabriuscula |
4. Stems leafy in proximal 1/2 – 2/3; peduncles 5–20 cm; involucres 12–20 × 20–35 mm | X. venusta |
5. Shrubs; stems branched to near apices; style-branch appendages shorter than stigmatic lines; s California | → 6 |
5. Subshrubs or perennials; stems branched mostly in proximal 3/4; style-branch appendages longer or shorter than stigmatic lines; various regions | → 7 |
6. Younger stems and branchlets stipitate-glandular; phyllaries loosely appressed, out-ermost stipitate-glandular (at least margins), innermost shorter than mid | X. cognata |
6. Younger stems and branchlets eglandular; phyllaries tightly appressed; outermost glabrous, innermost equaling or longer than mid | X. orcuttii |
7. Leaf blades spatulate to obovate or oblong, rarely elliptic; Texas | X. wrightii |
7. Leaf blades linear-lanceolate to lanceolate, oblanceolate, or elliptic-oblong; n to w of Texas | → 8 |
8. Leaf blades 2.5–6 mm wide, usually shallowly spinulose-toothed, sometimes entire; rays 13–17, white | X. cronquistii |
8. Leaf blades 3–20(–25) mm wide, sharply spinulose-toothed; rays (15–)18–60(–85), usually lavender, seldom white | X. tortifolia |
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USDA Plants Database
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