2. Juniperus virginiana L. var. virginiana (red cedar) Pl.
20c,d,e,f; Map 71
J. virginiana var. crebra Fernald & Griscom
Trees to 10(–20) m tall, rarely several-trunked and shrublike.
Trunks with brown to reddish brown bark shredding in longitudinal strips.
Scalelike leaves 1.5–4.0 mm long, acute at the tip. Needlelike leaves 4–10 mm
long. Cones 4–7 mm in diameter, 1- or 2-seeded. 2n=22, 33. Pollen shed
March–May.
Common throughout Missouri (eastern U.S. and adjacent Canada west to Nebraska). Limestone and dolomite glades and bluffs, less commonly on acidic
substrates, roadsides, fencerows, pastures, old fields, and other types of
disturbed areas with poor soils.
Another variety, var. silicicola (Small) E. Murray, is
restricted to coastal areas in the southeastern United States and differs in
its smaller cones, more spreading habit, and blunter leaf tips. For a
discussion of the separation of J. virginiana from J. ashei and
the lack of hybridization between the two, see the treatment of J. ashei.
Additionally, there is evidence that J. virginiana has undergone
introgressive hybridization with the western J. scopulorum Sarg. in the Missouri River Basin across the state (Van Haverbeke, 1968; Flake et al., 1978). True J.
scopulorum, the Rocky Mountain juniper, has the scale-leaves more widely
spaced on the branchlets and the bark shedding in plates and grows throughout
the Rocky Mountains as far east as western Nebraska and South Dakota. The
hybrids reported from Missouri are quite difficult to separate morphologically
from typical J. virginiana and differ primarily in quantitative features
of leaf morphology and position as well as in subtle differences of the
branching pattern. They differ more substantially in the chemical composition
of their resins. Thus far, hybrid populations have been confirmed from Benton, Callaway, Howard, Jefferson, and St. Charles Counties.
In Missouri, several races of eastern red cedar exist that
differ in details of their growth forms and that are generally undeserving of
formal taxonomic recognition. Some of the most interesting specimens are gnarled
individuals clinging to crevices of dry, exposed, dolomite bluffs along streams
and rivers in the Ozarks that may be several hundred years old. More recently,
the species has become much more common in the state and invasive in a variety
of dry, open habitats. It has closed in a significant proportion of the state's
dolomite and limestone glades during the past 70 years, due to the suppression
of fires, the exclusion of cattle and hogs from many of these areas, and
perhaps also the increased spread of seeds by introduced bird species.
A notable fungal disease of J. virginiana is cedar apple
rust (Gymnosporangium spp.), which is very common and causes the
formation of large, spherical galls on the branch tips. These usually form in
the fall, overwinter, then release long, gelatinous, fingerlike structures
containing teleospores through pores in the gall during the spring. The fungus
requires various members of the apple tribe, Maloideae, of the Rosaceae to act
as host plants for the remainder of its life cycle. See the treatment of the
genus Crataegus (Rosaceae) for further discussion.
The wood of eastern red cedar is durable and resinous. It has
been used for fence posts, lumber, shingles, and siding for houses and other
construction projects, pencils, chests, and handicrafts. The resin is refined
to produce an oil that is used for ointments, liniments, soaps, and shoe
polishes. The trees also are planted as ornamentals and in projects to reclaim
land following strip mining or farming.