Cercocarpus betuloides var. traskiae

(Eastwood) Dunkle

Bull. S. Calif. Acad. Sci. 39: 2. 1940.

Common names: Santa Catalina mountain mahogany
Conservation concernEndemic
Basionym: Cercocarpus traskiae Eastwood Proc. Calif. Acad. Sci., ser. 3, 1: 136, plate 11, fig. 7. 1898
Synonyms: C. betuloides subsp. traskiae (Eastwood) A. E. Murray C. montanus var. traskiae (Eastwood) F. L. Martin
Treatment appears in FNA Volume 9. Treatment on page 335. Mentioned on page 333.

Shrubs or trees, 10–30 (–80) dm. Young stems woolly with tightly coiled hairs. Leaves: stipules 5–10 mm; blade ovate to broadly ovate, obovate, suborbiculate, or oblongelliptic, (15–) 25–50 (–62) × (11–) 17–35 (–45) mm, strongly coriaceous, margins crenate, often strongly revolute, dentate-serrate in distal 1/2–3/4, abaxial veins densely and ± persistently white villous to woolly with loosely curved, 1/2 coiled at base, or coiled hairs 0.5–2 mm, areoles canescent, adaxial surface shiny, moderately hairy or glabrate. Flowers 3–8 (–16) per short-shoot; hypanthial tubes woolly with tightly coiled hairs. Achenes 7–11 × 1.8–2.3 mm; fruiting pedicels 6–10 mm; hypanthial tubes 9–11.5 mm; pedicel/tube ratio 52–69%; fruit awns 5–6 cm.


Phenology: Flowering Mar–Apr.
Habitat: Metamorphosed volcanic soil
Elevation: 100–300 m

Discussion

Of conservation concern.

Variety traskiae is known from a south-facing, steep canyon on Santa Catalina Island, where it grows on a highly mineralized metamorphic igneous-derived saussurite gabbro substrate, one not exposed elsewhere in southern California. The population now consists of 11 adult plants, down from 40–50 plants in 1898, the reduction attributed to herbivory by introduced mammals. In molecular studies summarized by L. H. Rieseberg and D. Gerber (1995), only six plants were considered pure traskiae; five were hybrids or introgressants with the insular phase of var. blancheae. The areas around several var. traskiae trees have been fenced to allow for recruitment.

Variety traskiae differs from var. blancheae in thicker, more coriaceous leaves with revolute margins that often obscure the marginal teeth, and thick, woolly tomentum of mostly coiled hairs on the abaxial leaf surface, pedicels, and hypanthial tubes. The thick vestiture can weather away over time.

Plants grown in gardens from cuttings of pure traskiae often lose the thick leaves, thick cuticles, and revolute margins that characterize the taxon in its native habitat, indicating that the diagnostic morphological traits in part may be a phenotypic response to its arid environment and perhaps its peculiar soil type.

Selected References

None.

Lower Taxa

None.
villous +, pilose +  and sericeous +
villous +  and woolly +
1.1 cm11 mm <br />0.011 m <br /> (1.35 cm13.5 mm <br />0.0135 m <br />) +
1.1 cm11 mm <br />0.011 m <br /> (2.1 cm21 mm <br />0.021 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.29 cm2.9 mm <br />0.0029 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
6mm +  and 10mm +
1.8mm +  and 2.3mm +
glabrate +  and hairy +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
James Henrickson +  and Brian D. Vanden Heuvel +
(Eastwood) Dunkle +
maroon-brown +, silvery +  and dark gray or brownish black +
compound +  and simple +
opposite +  and alternate +
cordate +, cuneate +  and rounded +
Cercocarpus traskiae +
5 cm50 mm <br />0.05 m <br /> (6.2 cm62 mm <br />0.062 m <br />) +
5 cm50 mm <br />0.05 m <br /> (7.8 cm78 mm <br />0.078 m <br />) +
3.5 cm35 mm <br />0.035 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (5 cm50 mm <br />0.05 m <br />) +
ovate +  and broadly ovate obovate suborbiculate or oblongelliptic +
0.5 cm5 mm <br />0.005 m <br /> (5 cm50 mm <br />0.05 m <br />) +
17mm +  and 35mm +
free +  and distinct +
Santa Catalina mountain mahogany +
hemispheric-campanulate +
not +  and aggregated +
100–300 m +
eglandular +  and veined +
hairy +  and glabrous +
0.1 cm1 mm <br />0.001 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
3 +  and 8 +
unisexual +  and bisexual +
not +  and aggregated +
8.5 cm85 mm <br />0.085 m <br /> (12.5 cm125 mm <br />0.125 m <br />) +
5 cm50 mm <br />0.05 m <br /> (6 cm60 mm <br />0.06 m <br />) +
1.1 cm11 mm <br />0.011 m <br /> (1.35 cm13.5 mm <br />0.0135 m <br />) +
cylindro-fusiform +
0.6 cm6 mm <br />0.006 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
chartaceous-coriaceous +
Metamorphosed volcanic soil +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
spreading +  and erect-ascending +
curled +  and wavy +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1.3 cm13 mm <br />0.013 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
0.9 cm9 mm <br />0.009 m <br /> (1.15 cm11.5 mm <br />0.0115 m <br />) +
villous +, hirsute-pilose +  and sericeous +
cinnamon brown +, tinged reddish +  and greenish yellow +
1-3(-18)-flowered +
crassinucellate +
drought-deciduous +  and persistent +
reduced +
flexuous +  and straight +
2 cm20 mm <br />0.02 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
glabrescent +  and hairy +
0.3 cm3 mm <br />0.003 m <br /> (2 cm20 mm <br />0.02 m <br />) +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0 (?) +  and 4 (?) +
free +  and distinct +
5 +  and 4 +
0.9 cm9 mm <br />0.009 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
Flowering Mar–Apr. +
adnate +, free +, connate +  and distinct +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Bull. S. Calif. Acad. Sci. +
not arillate +
deciduous +
free +  and distinct +
erect +  and reflexed +
acute-acuminate +  and deltate +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
not +  and branched +
3 cm30 mm <br />0.03 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Conservation concern +  and Endemic +
free +  and distinct +
1 +  and 20 +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
adnate +  and free +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
persistent +
distinct +
basal +, lateral +, subterminal +  and terminal +
elongate +
C. betuloides subsp. traskiae +  and C. montanus var. traskiae +
Cercocarpus betuloides var. traskiae +
Cercocarpus betuloides +
variety +
inconspicuous +
hemispheric +
tree +  and shrub +