Adenostoma

Hooker & Arnott

Bot. Beechey Voy., 139. 1832.

Common names: Chamise
Etymology: Greek a den, gland, and stoma, mouth, alluding to gland at rim of hypanthium
Treatment appears in FNA Volume 9. Treatment on page 392. Mentioned on page 393, 395.

Shrubs, erect to rounded-spreading, 8–60 dm; developing enlarged woody lignotubers. Stems 1–10+, erect to arching or spreading, branched, terete or decurrently grooved; bark of red brownish papery layers, weathering gray; short-shoots present or absent; hirtellous, pilose, or glabrous. Leaves persistent, cauline, alternate, sometimes opposite, juvenile 1–2-pinnatifid, mature simple; stipules reduced or absent; petiole present or absent; blade linear to terete or linear-oblanceoloid, (0.2–) 0.3–1.4 (–2.6) mm, leathery or not, base persistent, clasping, truncate, margins revolute, entire, abaxial surface glabrous or sessile-glandular. Inflorescences terminal, 2–400+-flowered, panicles well branched, pyramidal or racemes or spikes reduced to cylindric, glabrous or hirtellous; bracts present; bracteoles present. Pedicels absent or relatively short. Flowers 2–6 mm diam.; hypanthium cylindric to campanulate, inner rim annular gland thickened, undulate, 0.6–2.4 mm, glabrous or hirtellous; sepals 5, erect to reflexed, valvate, broadly ovate to semiorbiculate; petals 5, white becoming rusty brown, obovate-orbiculate or elliptic to ovate, base clawed; stamens 10 or 15 in groups of 2 or 3 alternate with petals, shorter than petals; carpels 1 (or 2), distinct, obliquely truncate distally, glabrous or sericeous, styles lateral, each bending over ovary, erect distally, stigmas capitate to truncate; ovules 1 (or 2). Fruits achenes, 1 (or 2), obovoid or ellipsoid, 1.1–1.8 (–2.4) mm, hirtellous distally (exposed part); hypanthium persistent; sepals persistent, moreorless spreading; styles not persistent. x = 9.

Distribution

Calif., nw Mexico

Discussion

Species 2 (2 in the flora).

Adenostoma is a Madro-Tertiary derivative of a lineage with compound leaves. Seedlings and sucker shoots have 1–2-pinnatifid leaves; mature leaves are simple, undivided. Both species occur in chaparral and resprout after fires from basal lignotubers. The single achenes are derived from ancestral 5-follicled fruits, each carpel retaining the ancestral marginal style. Stamens are arranged in groups of 2 to 3 alternate with petals; filaments expand sequentially, first 5 (1 opposite each sepal), followed by the second 5 and third 5 (when 15).

Selected References

None.

Key

1 Leaves crowded on short shoots, blades dark green, adaxial surfaces glabrous; stipules present on long-shoot leaves; subtending flower bracts 3-lobed, medial lobe largest; bracteoles 2, subulate; stamens (10–)15. Adenostoma fasciculatum
1 Leaves on slender long shoots (short-shoot fascicles absent), blades yellow-green, adaxial surfaces sparsely hirtellous and sessile-glandular; stipules absent; subtending flower bracts linear-subulate; bracteoles 5 or 6, outermost subulate, inner oblong-obovate; stamens 10(–12). Adenostoma sparsifolium
... more about "Adenostoma"
sessile-glandular +  and glabrous +
William Jones +  and James Henrickson +
Hooker & Arnott +
compound +  and simple +
opposite +  and alternate +
persistent +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
linear +  and terete or linear-oblanceoloid +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
? (?) +  and ? (?) +
sericeous +  and glabrous +
opposite +  and alternate +
mature +  and juvenile +
1-2-pinnatifid +
Chamise +
Calif. +  and nw Mexico +
not +  and aggregated +
Greek a den, gland, and stoma, mouth, alluding to gland at rim of hypanthium +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
not +  and aggregated +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
ellipsoid +  and obovoid +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
hirtellous +  and glabrous +
undulate +  and annular +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.24 cm2.4 mm <br />0.0024 m <br />) +
crassinucellate +
red brownish +
opposite +  and alternate +
persistent +
toothed +, unlobed +  and lobed +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
pyramidal +
0 (?) +  and 4 (?) +
free +  and distinct +
adnate +, free +, connate +  and distinct +
Bot. Beechey Voy., +
hirtellous +  and glabrous +
cylindric +
reduced +
not arillate +
persistent +
free +  and distinct +
spreading +, erect +  and reflexed +
broadly ovate +  and semiorbiculate +
glabrous +, pilose +  and hirtellous +
hirtellous +  and glabrous +
cylindric +
reduced +
free +  and distinct +
grooved +  and branched +
erect +  and arching or spreading +
1 +  and 10 +
capitate +  and truncate +
adnate +  and free +
not persistent +
distinct +
erect +  and bending +
not elongate +
Adenostoma +
Rosaceae tribe Sorbarieae +
inconspicuous +
erect +  and rounded-spreading +