Arbutus xalapensis

Kunth in A. von Humboldt et al.

in A. von Humboldt et al., Nov. Gen. Sp. 3(fol.): 219.

,

3(qto.): 279. 1819 ,.

Common names: Texas madrone
Synonyms: Arbutus texana Buckley Arbutus xalapensis var. texana (Buckley) A. Gray
Treatment appears in FNA Volume 8. Treatment on page 400. Mentioned on page 398, 399.

Shrubs or trees, 2–4 (–8) m; bark brick-red, peeling in smooth flakes over most larger limbs, retained on base of trunk on older specimens and eventually over most of oldest parts of plant, becoming gray, irregularly roughened (twigs of newly emerging shoots usually densely villous, often with mixture of glandular-hairs, fully developed twigs hairy and/or glandular-hairy, or glabrate or glabrous, twig bark soon loosening and exfoliating, older twigs usually smooth, brick-red or glaucous-grayish red). Leaves ± equal in size throughout; petiole 1.2–2.5 cm, base slightly decurrent, glabrate; blade green or slightly lighter green abaxially, pale or bright olive-green or glaucous-green, elliptic or slightly ovate-elliptic, (2.5–) 4–6 (–7.5) × (1.2–) 1.8–3 (–4) cm, base usually tapered, rarely slightly cordate, (margins smooth or irregularly toothed on sprouts), apex acute or obtuse, surfaces glabrous or ± hairy. Inflorescences (often showy), varying from densely clustered or openly-branched to relatively few-flowered; axes hairy, with both glandular and eglandular hairs intermixed. Pedicels accrescent, obliquely erect to pendulous, 1.6–3.2 mm, hairy, with both glandular and eglandular hairs intermixed; bract (accrescent), clasping base, reddish or tan, scalelike, 1.3–2 mm (to 2.9–3 mm in fruit). Flowers: calyx tan (sometimes with blush of pink), (1.8–3 mm), lobes 1–1.2 mm, apex obtuse or rounded; corolla 5.1–5.4 (–6.1) mm (the larger on rapidly developing, more open, and elongated inflorescences); anthers ca. 1.5 mm, spurs 1/2–3/4 times length of thecae; ovary with 2–3 (–5) ovules per locule. Berries deep red or blackish red, 5.5–7.5 mm diam. Seeds 2.5–3 mm. 2n = 26.


Phenology: Flowering (Feb-)Mar–Apr(-May); ripe fruit appears after about 6 weeks.
Habitat: Rough, stony hills, mountain slopes, calcareous ledges
Elevation: 300-2200 m

Distribution

V8 754-distribution-map.gif

N.Mex., Tex., Mexico, Central America

Discussion

Arbutus xalapensis is frequent in the Edwards Plateau hill country southwest of Austin, Texas, where it is associated with junipers, oaks, and mesquite at moderate elevations. Westward, in the Chisos, Davis, and Guadalupe mountains, it occurs in the pinyon-juniper zone at higher elevations (to 2200 meters). In the Animas Mountains of Hidalgo County, southwestern New Mexico, A. xalapensis has limited contact with A. arizonica, and some herbarium specimens suggest that hybridization occurs there. Confirmation will require a more detailed analysis of those populations.

Selected References

None.

Lower Taxa

None.

"entire" is not a number.

... more about "Arbutus xalapensis"
1.5 cm15 mm <br />0.015 m <br /> (?) +
Rounded (?) +, Obtuse (?) +  and Acute (?) +
Paul D. Sørensen +
Kunth in A. von Humboldt et al. +
not furrowed +
gray +  and brick-red +
exfoliating +
tan +  and reddish +
scale-like;cordate;tapered;decurrent +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
blackish red +, red +  and deep +
0.55 cm5.5 mm <br />0.0055 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
hairy +  and glabrous +
roughened-tuberculate +
6 cm60 mm <br />0.06 m <br /> (7.5 cm75 mm <br />0.075 m <br />) +
3 cm30 mm <br />0.03 m <br /> (4 cm40 mm <br />0.04 m <br />) +
glaucous-green +, bright olive-green +, pale +, , +, lighter green +  and green +
4 cm40 mm <br />0.04 m <br /> (6 cm60 mm <br />0.06 m <br />) +
ovate-elliptic;elliptic +
coriaceous +
1.8cm;3cm +
glabrous +, tomentose +  and glandular-hairy +
Texas madrone +
0.54 cm5.4 mm <br />0.0054 m <br /> (0.61 cm6.1 mm <br />0.0061 m <br />) +
rotate to crateriform campanulate cylindric globose or urceolate +
0.51 cm5.1 mm <br />0.0051 m <br /> (0.54 cm5.4 mm <br />0.0054 m <br />) +
N.Mex. +, Tex. +, Mexico +  and Central America +
300-2200 m +
undifferentiated +
fusiform +
stonelike +
expanded +  and slender +
indehiscent +
Rough, stony hills, mountain slopes, calcareous ledges +
multicellular +
openly-branched +  and relatively few-flowered +
isofacial +  and bifacial +
opposite +, whorled +  and alternate +
persistent +
1mm +  and 1.2mm +
plane;entire or;finely coarsely toothed +
parietal +, axile +  and placentation +
tenuinucellate +  and unitegmic +
oldest +  and older +
obliquely erect +  and pendulous +
accrescent +
0.16 cm1.6 mm <br />0.0016 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
reduced +
not sticky +
1.2 cm12 mm <br />0.012 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Flowering (Feb-)Mar–Apr(-May) +  and ripe fruit appears after about 6 weeks. +
4-5-carpellate +
oldest +  and older +
subterminal +
in A. von Humboldt et al., Nov. Gen. Sp. +
not connate +
distinct +
globose +
2.5mm +  and 3mm +
persistent +
ovate +  and deltate +
elongating +
1/2-3/4 times length of thecae +
peltate +  and capitate +
straight +
hairy +  and glabrous +
Arbutus texana +  and Arbutus xalapensis var. texana +
Arbutus xalapensis +
species +
achlorophyllous +  and chlorophyllous +
evergreen +, deciduous +  and perennial +
tree +  and shrub +
heterotrophic +, autotrophic +  and mycotrophic +