Description:
This
wildflower is a winter annual about 4-12" tall. The stems are either
unbranched, or they branch at the base of each plant; they are pale
red, terete, glabrous, and glaucous. Alternate leaves are arranged
somewhat densely around the stems; they are about ½-1" long, 2-3 mm.
across, and
ascending to widely spreading. Individual leaves are pale green, linear
in shape, subterete (circular, but slightly flattened in
cross-section), and glabrous. The leaf bases slightly clasp the stems;
each leaf has a pair of minute auricles (ear-like lobes) at its base.
Each stem terminates in a cyme of flowers up to 6" across. Each cyme
has 3-7 horizontal branches that are spaced widely apart; the
flowers are densely arranged along the upper sides of these branches
(typically 10-40 flowers per branch). The flowers are sessile or nearly
sessile (on pedicels less than 1 mm. in length). Each flower spans
about ½" across, consisting of 4 pink petals (rarely white), 4 pale
green sepals, a cluster of 4 pistils, and 8 stamens. The petals and
sepals are linear-lanceolate in shape; the petals are about twice the
length of the sepals. The narrowly ovoid pistils are light pink (less
often white) during the blooming period; each pistil has a single
style. The anthers are initially dark red, but they turn black
shortly afterwards. Among the flowers, there are bracts
that resemble the leaves, except they
are about
one-half the size of the latter. The blooming period occurs during late
spring to early summer, lasting about 1 month. Afterwards, the flowers
are replaced by clusters of 4 spreading follicles; these follicles are
about ¼" long, narrowly ovoid in shape, and prominently beaked.
Immature follicles are pale green, but at maturity they turn brown.
Eventually, each follicle splits open along one side to release
numerous seeds. The root system is fibrous. This wildflower spreads by
reseeding itself. At favorable sites, it often forms colonies of plants.
Cultivation:
The preference is full sun, dry conditions, and thin rocky
soil. Partial sun is tolerated, although there will be a greater
tendency for individual plants to sprawl in the direction of greater
light. Seeds typically germinate in the fall, allowing young plants to
overwinter in a dormant state. Most growth and development occur during
the
spring. The leaves wither away during the hot weather of summer as
individual plants die down. This plant has a crassula acid metabolism
(CAM) that enables it to survive in xeric conditions. Like other
sedums (
Sedum spp.),
Widow's Cross can be cultivated in sunny rock
gardens.
Range
& Habitat: The native Widow's Cross occurs in
southern
Illinois, where it is uncommon. Illinois lies
along the northern range of this species. Habitats include rocky
cliffs, exposed rocky ledges, and rocky glades, particularly in areas
where there is exposed flat bedrock. The underlying bedrock in these
habitats consists of sandstone, limestone, or chert. Widow's Cross is a
highly specialized plant that is found in high quality natural areas.
Faunal
Associations: Very little is known about floral-faunal
relationships for this species. Generally, the flowers of sedums (
Sedum
spp.) are cross-pollinated by small bees (
Andrena spp., etc.)
and
probably other insects. Both nectar and pollen are available as floral
rewards to such visitors. In areas where Widow's Cross and other sedums
are cultivated (especially nurseries and greenhouses), they may be
attacked by
Aphis sedi
(Sedum Aphid). This aphid was introduced into North
America from Eurasia.
Photographic
Location: A rocky ledge in southern Illinois.
Comments: Other common names for Widow's Cross (
Sedum pulchellum)
are
Limestone Stonecrop and Rock Stonecrop. Widow's Cross is normally an
attractive little plant with pink flowers.
It is one of only a few native
Sedum
spp. that are found in the rocky
hills of southern Illinois and the surrounding area. Several species of
cultivated sedums from Eurasia occasionally escape and naturalize in
open disturbed habitats, but they usually don't persist (with the
exception of
Sedum acre).
Widow's Cross can be distinguished from these
other species by its pink 4-petaled flowers, widely spreading branches
of its inflorescence, and small linear leaves that are nearly terete.
Other sedums often have white or yellow flowers, flowers with 5 petals,
inflorescences with ascending branches, or leaves that are more
flattened and wide than those of Widow's Cross.