1. Berberis L. (barberry)
Plants shrubs.
Stems with the leaves mostly replaced by spines, the normal foliage leaves
clustered on very short shoots in the axils of the spines. Leaves many per
plant, simple and unlobed, pinnately veined. Inflorescences axillary racemes or
umbels, or flowers rarely solitary in leaf axils. Flowers with 3 small
bractlets immediately below the calyx. Sepals 6, 3–5 mm long, petaloid, yellow.
Petals 6, 2.5–3.0 mm long, yellow, bearing nectaries. Stamens 6, the anthers
attached at the middle, opening by 2 apical flaps. Fruits berries. Seeds 4–6 mm
long, narrowly to broadly ovoid, the seed coat hard, tan or more commonly
reddish brown to black. About 500 species, North America, Europe, Asia, and the
mountains of South America and east Africa.
The Missouri
species of Berberis are deciduous shrubs with spiny stems, simple
leaves, lax inflorescences, and red berries, but many species from other parts
of the world are quite different. One such species, B. aquifolium Pursh
(Mahonia aquifolium (Pursh) Nutt.), is widely grown as an ornamental in
Missouri under the name Oregon grape. It is an unbranched evergreen shrub with
spineless stems, pinnately compound leaves with spiny hollylike leaflets, dense
racemes 3–11 cm long with 30–60 flowers, and glaucous blue berries. It has been
reported to escape from cultivation occasionally in Michigan and eastern
Canada, and it might be capable of persisting outside of cultivation in
Missouri, at least briefly.
Many species of Berberis
are grown as ornamental shrubs. However, some species serve as the alternate
host for Puccinia graminis Pers., the fungus that causes black stem rust
of wheat and other grain crops. Puccinia graminis has a two-phase life
cycle, with the dikaryotic (telial and uredinial) stage attacking grains and
wild grasses and the homokaryotic (aecial) stage attacking some species of Berberis
(Alexopoulos et al., 1996). The fungus can overwinter on grasses only in areas
with mild winters, but it overwinters on Berberis species even in very
cold climates, so the presence of susceptible Berberis species can
greatly increase losses from this fungus in nearby grain fields. Farming is
only affected when susceptible barberries grow in open areas adjacent to grain
fields; plants in wooded areas or areas remote from farmland have no
significant impact on crops. The sale, transport, or cultivation of susceptible
or untested species of Berberis is now banned by state and federal
quarantine regulations, and extensive eradication programs have almost
eliminated susceptible barberries (primarily B. vulgaris) in many areas
where they once grew (Fulling, 1943; Roelfs, 1982). Because of this, barberries
no longer affect grain growing in the United States, but quarantine laws are
still enforced in order to prevent susceptible species from becoming reestablished
in farming areas in the future (Roelfs, 1982).
Aside from the
berries of some species, barberry plants are variously considered poisonous.
Decoctions of a few species were used by Native Americans to treat sore
throats, infected gums, jaundice, and diarrhea (Moerman, 1998).