Arctostaphylos
uva-ursi (L.) Spreng.
Standardized Common
Name: Uva-Ursi
Other Common Names: Bearberry,
Kinnikinick
Family: Ericaceae
Taxonomy: The genus includes
about 50 species, most confined to western North America. A. uva-ursi is
circumpolar and widely distributed in North America, Europe and Asia. In North
America, it is a polyploid complex with at least three main ploidy levels. A
number of subspecies or varieties that differ in types of pubescence have been
described. Rosatti showed that the American varieties are often commingled in
nature and that varying environmental conditions could produce different
“subspecies” from the same individual; thus, these varieties should not be
recognized at all. However, Fromard found that in Europe there was a distinct
separation between a northern diploid type and a southern tetraploid type, with
the latter having a greater diversity of flavonols and anthocyanins in Spain
and France.
Description: Prostrate creeping
shrub, sometimes vinelike; stems slender, much-branched, with peeling bark, the
younger pubescent with combinations of short or long, glandular or
non-glandular hairs. Leaves alternate, short-petioled, entire, obovate to
spatulate or elliptical, 1–3 cm long, evergreen, thick and leathery, glabrate
at maturity; base tapering; apex rounded to slightly obtuse or emarginate;
upper surface glossy, lower surface dull, pale, with raised midrib.
Inflorescence a small, few-flowered raceme. Sepals 5; corolla fused, urceolate
(urn-shaped, narrowed at the mouth), pink to white, 4–5 mm long, with 5
reflexed lobes; stamens 10, in two whorls; ovary superior, 5-loculed. Fruit a
drupe, red, 3–11 mm in diameter.
Parts
in Commerce:
Leaves
Identification:
- Usually obovate,
ranging to oblanceolate, spathulate or elliptical
- 1–3 cm long,
4–14 mm broad
- Base tapering to
very short (1–5 mm) petiole
- Apex rounded,
sometimes rounded-obtuse or slightly emarginate
- Margins entire
or barely revolute
- Texture leathery
- Petiole and
margins frequently pubescent with soft, weak white hairs
- Upper surface
pale to olive green, sometimes brown-tinged, glossy, glabrous
- Lower surface
dull pale or greyish green, glabrous or, in young leaves, very sparsely
pubescent on midrib or throughout
- Midrib visible
for most of length of leaf; secondary veins inconspicuous, mostly short,
netted, sometimes a few long and emerging from midrib at narrow acute
angle; venation slightly raised and darker than blade below, slightly
sunken above
- Taste astringent
Adulterants: The only other
European species of Arctostaphylos is quite different in appearance and
could not readily be substituted. Wichtl indicates that material from Mexico
and the southern United States may be adulterated with Arctostaphylos
pungens H.B.K., which does not contain arbutin (believed to be the most
important active compound). Leaves of A. pungens are sometimes larger
than those of A. uva-ursi, up to over 4 cm long with petioles to over 1
cm long, and are more typically elliptical than obovate. The leaf apex is
almost always acute or mucronulate; the elongated straight secondary veins are
frequently more conspicuous; and young leaves are more densely pubescent
especially on the petioles, with the upper surface often pubescent as well.
Vaccinium
vitis-idaea
L. (Ericaceae), a cranberry relative, is another historical adulterant. The
lower surface is pale with scattered dark stiff trichomes and lacks visible
secondary venation; the margins are strongly revolute; and the upper surface
may be dark green and may have conspicuous secondary venation or short hairs
along the midrib.
References:
Fernald ML. Gray’s Manual of Botany, 8th ed. New York: American Book
Company; 1950:1126–1127.
Fromard F. Systématique du taxon Arctostaphylos
uva-ursi, Ericaceae, en Europe: données nouvelles concernant les
populations pyrénéenes et circumpyrénéennes. Canad J Bot.
1987;65:687–695.
Rosatti TJ. Field and garden studies of Arctostaphylos
uva-ursi (Ericaceae) in North America. Syst Bot. 1987;12:61–77.
Webb DA. Arctostaphylos. In: Tutin TG, Heywood VH, Burges NA, et al.,
eds. Flora Europaea. Vol. 3. Cambridge: Cambridge University
Press; 1972:11.
Wichtl M, ed. Herbal Drugs and
Phytopharmaceuticals, 3rd English
ed. Stuttgart: medpharm Scientific Publishers and Boca Raton, FL: CRC Press;
2004:626–629.
Figure 7: a—b, Arctostaphylos uva-ursi, leaf and
close-up.
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