Description:
This woody plant is a large shrub or small tree about 10-25' tall that
has a short trunk up to 1' across and a broad spreading crown. It is
moderately to densely divided into crooked branches, short lateral
spurs, and twigs. The trunk bark of mature trees is mostly gray, scaly,
and thin; the irregular furrows and fissures separating the scales are
narrow, shallow, and often reddish brown. Branch bark is mostly gray
and more smooth with scattered white lenticels (air pores); sometimes
it has a reddish brown tint. Twigs are gray to reddish brown and smooth
to slightly pubescent; they also have scattered white lenticels. The
short lateral spurs are oriented at a right-angle from their branches;
they are similar to the twigs, except they sometimes develop into
thorns. Young shoots are light green, terete, and densely pubescent.
Alternate leaves occur along the shoots, young twigs, and short lateral
spurs; they often appear densely clustered. The leaves are 1½–4" long
and 1-2" across; they are ovate or oblong-ovate in shape, while their
lower-middle to upper margins are crenate-dentate and often shallowly
cleft into short irregular lobes. The bases of leaves are rounded
to broadly wedge-shaped and entire (both toothless and lobeless), while
their tips are obtuse. The upper leaf surface is medium green and
glabrous (although short-pubescent when very young), while the lower
leaf surface is densely short-pubescent to pubescent and pale
green to white. Leaf venation is pinnate. The petioles are ½–1½" long,
densely pubescent, and more or less whitened.
Clusters of 2-6 flowers
develop from the tips of twigs and short lateral spurs. The pedicels of
these flowers are ¾–1½" long and densely pubescent. Individuals flowers
are 1¼–2" across; each flower consists of 5 light pink to nearly white
petals, a green cup-shaped calyx with 5 teeth, 10-20 stamens with
yellow anthers, and a pistil with 5 styles. The widely spreading petals
are oval in shape, except they taper abruptly to become narrow at their
bases. The calyx and its teeth are pubescent on both the exterior and
interior surfaces; the teeth are linear-lanceolate to narrowly
triangular in shape. The large flower buds are usually bright pink. The
blooming period occurs during the late spring, lasting about 1-2 weeks.
The diurnal flowers have a tendency to bloom at about the same time,
and they are fragrant. Afterwards, fertile flowers will be replaced by
fruits (pomes) that become 1–1¼" across at maturity; they are
subgloboid to globoid in shape, except at their apices and bottoms,
where they are indented. Mature fruits are greenish yellow with waxy
exteriors, while their interiors are fleshy, firm, and white; each
fruit contains up to 10 seeds. The flavor of mature fruits is sour and
bitter. The seeds are dark-brown, flattened, and tear-drop shaped. The
root system is woody and spreading; it is capable of developing clonal
offsets from underground runners, especially when this woody plant
has been top-killed by fire or some other catastrophe.
Cultivation:
The preference is full or partial sun, moist to mesic conditions, and
soil containing loam, clay-loam, or some rocky material. Like other
apples and crab apples (
Malus
spp.), this woody plant is vulnerable to
many disease organisms and insect pests. Nonetheless, if conditions are
favorable, it can be long-lived, exceeding 50 years of age.
Range
& Habitat: The
native Prairie Crab Apple occurs in almost all counties of Illinois,
where it is occasional (see
Distribution
Map). Populations of this species have declined
because of habitat destruction. It is largely endemic to the midwestern
United States (upper Mississippi valley), although widely scattered
populations of this species occur further south. Habitats include open
woodlands, savannas, thickets, woodland borders, limestone glades,
prairies, hill prairies, semi-open areas along streams, edges of
pastures and fields,
fence rows, and powerline clearances in wooded areas. Prairie Crab
Apple requires some disturbance in order to establish itself and
thrive, although excessive disturbance will eliminate it.
Faunal
Associations: The value of Prairie Crab Apple to various
kinds of
wildlife is quite high. The nectar and pollen of the large flowers
attract honeybees, bumblebees, and other long-tongued bees; they are
probably the primary agents of cross-pollination. Other visitors of the
flowers include smaller bees, butterflies, and skippers. A variety of
insects feed destructively on the foliage, fruit, flowers, wood,
and plant juices of crab apples and apples (
Malus spp.),
including
Prairie Crab Apple. These insect feeders include leafhoppers
(
Eratoneura hartii,
Erythridula dowelli,
Erythridula lawsoniana,
Typhlocyba pomaria)
and such aphids as the Green Apple Aphid (
Aphis
pomi), Rosy Apple Aphid (
Dysaphis plantaginea),
Woolly Apple Aphid
(
Eriosoma lanigerum),
and Apple-grass Aphid (
Rhopalosiphum
oxyacanthae). Other miscellaneous pests include the Apple
Red Bug
(
Lygidea mendax),
larvae of the Apple Twig Borer (
Amphicerus
bicaudatus), larvae of the Flat-headed Apple Tree Borer (
Chrysobothris
femorata), larvae of the Round-headed Apple Tree Borer (
Saperda
candida), the Apple Curculio (
Anthonomus quadrigibbus),
Apple Flea
Weevil (
Rhynchaenus
pallicornis), and Apple Maggot (
Rhagoletis
pomenella). The
Insect Table has a
more complete list of these species.
The larvae of a large number of moths also feed on various parts of
these woody plants. Some examples of these species include the Eastern
Tent Caterpillar (
Malacosoma
americanum), Fall Webworm (
Hyphantria
cunea), Apple and Thorn Skeletonizer (
Choreutis pariana),
Many-dotted
Appleworm (
Balsa malana),
Red-humped Appleworm (
Schizura
concinna),
Wild Cherry Sphinx (
Sphinx
drupiferarum), Lesser Appleworm (
Grapholita
prunivora), Pale Apple Leafroller (
Pseudexentera mali),
and Apple
Blotch Leafminer (
Phyllonorycter
crataegella). The
Moth Table has a
more complete list of these species. The larvae of two butterflies, the
Tiger Swallowtail (
Papilio
glaucus) and Striped Hairstreak (
Satyrium
liparops), sometimes feed on the leaves. The fruits of
Prairie Crab
Apple, other crab apples, and the cultivated apple are sources of
food to many mammals and birds. Mammals that eat these fruits include
the Black Bear, Coyote, Gray Fox, Red Fox, Opossum, Raccoon, Striped
Skunk, Spotted Skunk, Groundhog, Gray Squirrel, Fox Squirrel, and
White-tailed Deer (Martin et al., 1951/1961; Barnes, 1999). By eating
the fruits, these mammals spread the seeds of these woody plants to new
locations (Myers et al., 2004). The White-tailed Deer also browses on
the twigs and foliage, while the Cottontail Rabbit sometimes gnaws on
the bark of saplings during the winter (Sotala & Kirkpatrick,
1973;
Haugen, 1942).
Depending on the species, various birds feed on the
buds, fruits, and/or seeds of the Prairie Crab Apple, other crab
apples, and the cultivated apple. For example, the Ruffed Grouse,
Purple Finch, and White-throated Sparrow eat the buds, while the Hairy
Woodpecker, Starling, and Grackle peck at the fruits. The
Bird Table has a
more complete list of these species. Because these
woody plants, including Prairie Crab Apple, are often densely branched,
they provide good nesting habitat for the Yellow-breasted Chat, Orchard
Oriole, Song Sparrow, and other birds. Woodpeckers and other
insectivorous birds also
benefit from the large variety of insects that these woody plants
attract. Prairie Crab Apple, in particular, provides good cover for
many mammals and other kinds of wildlife because of its tendency to
form dense thickets from clonal offsets.
Photographic
Location: Edge of a woodland along a roadside in Champaign
County,
Illinois.
Comments:
Prairie Crab Apple (
Malus
ioensis) is one of three native crab apples
(
Malus spp.)
in Illinois. A second native species, Wild Crab Apple (
Malus
coronaria), is very similar in overall appearance, except
that its
leaves, young shoots, calyces, ovaries, and pedicels are hairless. This
latter species has a more eastern distribution than Prairie Crab Apple.
These two native crab apples
differ from many introduced crab apples from Eurasia by having leaves
with shallow lobes and greenish yellow fruits that exceed ¾" across.
They are also more likely to have thorns along their branches than
these
non-native species. A third native species, Southern Crab Apple (
Malus angustifolius),
is smaller in size than the preceding native crab apples, and its
leaves are more narrow in shape. In Illinois, this crab apple is found
in the southern section of the state. The flowers of native crab
apples are large,
fragrant, and showy during the short period when they bloom during the
spring. They are parent species of some crab apple cultivars that have
been developed as ornamental plants for landscapes. For example,
Bechtel's Crab Apple is a double-flowered cultivar that has Prairie
Crab Apple as a parent. In the past, the fruit of Prairie Crab Apple
was used to make apple
jelly, cider, and vinegar.