Documenting Diversity at the Katharine Ordway Natural History Study Area
Amelanchie, Amelanchier laevis, or Amelanchier arborea?
Phylum: Magnoliophyta / Angiospermae
Subfamily: Maloideae / Spiraeoideae
Species: laevis, arborea
laevis - Apple Severiceberry, Smooth Serviceberry, Juneberry
arborea - Downy Serviceberry, Shadbush
This species belongs to the genus Amelanchier. The
main characteristic that identifies this species within this genus is
the presence of white flowers with five petals. Other characteristics
that support the identification of this species include leaves with
saw-like edges and the small, shrub size of the whole tree. Lastly,
Amelanchier is a genus native to the North Temperate zone, which is
where this species is found.
This species sample was collected during the early
spring when the tree just starts to bud young flowers. As a result, the
foliages and flowers are not in their adult stages. This limits the
identification of this species as most of the Amelanchier in their
young stage look really similar. However, when comparing the morphology
of the young foliages with the Amelanchier database, this species is
likely to be either Amelanchier laevis or Amelanchier arborea.
According to Carl Otto Rosendahl’s method of
identifying Amelanchier, Amelanchier laevis and Amelanchier arborea
have a very similar morphology as they share almost exactly the same
“Flowers racemose, leaves rounded or subcordate at
the base, conduplicate in the bud, summit of ovary rounded…Leaves
serrate-dentate to finely serrate, at least in the upper third,
principal veins running branched or unbranched into the teeth… Leaves
finely toothed or serrate, main lateral veins not prominent, somewhat
irregularly and unequally spaced, usually with shorter intermediate
ones… Tall shrubs or small tree, not stoloniferous or forming colonies
(sometimes fastigate), leaves ovate, elliptic-ovate to slightly obovate
or elliptic to oblong, apex acute to more or less acuminate or
apiculate… Top of the ovary is glabrous1.”
The difference that separates A. laevis and A.
arborea is the morphology of their leaves. A. laevis leaves are densely
covered with tiny hairs. When flowering time arrives, the leaves become
small and folded. When mature, the foliage is pointy and ovate; the
petiole and the lower surface are also both covered with tiny hairs.
On the other hand, A. arborea leaves are devoid of hair, or have very
few hairs, during the unfolding time. The structure, however, is
similar to A. laevis. The structure of leaves when mature is also
similar to A. laevis, except that these have fewer, or even no, hair1,3.
It is difficult to specify whether the
collected sample belongs to the species A. laevis or A. arborea as the
tree is still young, and therefore so are the leaves. The hair on the
surface of the leaves is present in a few amounts, but this could be
attributed to the fact that the tree is still growing. When the leaves
mature, it may or may not be covered with hair in high density. The
fully grown tree may be 25 feet or 50 feet, in which observations over
a longer period of time would be needed in order to determine the
species of this collected sample.
A. arborea grows in a variety of habitats such as
swampy lowlands, dry woods, sandy bluffs, rocky ridges, forest edges,
open woodlands and fields4 but it mostly grows in rich woods, thickets,
and on hillsides. It is a small tree or multi-stemmed large shrub with
small arching, spreading branches. The tree can grow up to 50 feet
high, but it is short-lived. The leaves resemble those of apple trees,
their close relative. The leaves are simple with the length of 1-3
inches long. The colors of the leaves (when newly born) are purple/dark
green in the summer, and vary from yellow to red in the fall. The
flowers bloom in clusters with five petals of white flowers in early
spring, but only for a few days, then the color will change to rosy
pink. They are 2-4 inches in length. The fruits are small and fleshy
with seed chambers, which ripen in June. The color of the berry-like
fruit turns from green to purplish black. When this happens, the fruit
is eaten and dispersed by animals in the wild. The fruit is also a food
source for the larvae of tiger butterflies, gypsy moths and viceroys;
furthermore, they are the best source of food for birds during the
summer. The bark A. arborea is smooth and gray, but often with a
reddish cast. As the bark ages, it becomes ridged and scaly3.
A. laevis is a deciduous, multi-stemmed large shrub
or small tree with many small branches. The tree grows up to 25 feet
high. It has a rapid growth rate but is short-lived. The leaves are
simple, 1-3 inches in length. The color of the leaves during flowering
time is bronze/purple, but varies from yellow to red during the
fall1,2. The white flowers are in four-inch long clusters; the flowers
also have five petals. The sweet fruit are 3/8 of an inch in length,
with a rich purple-black color when it matures. They are also eaten and
dispersed by wildlife, especially birds. The bark of A. laevis is
reddish brown when young, but turns dull grayish when older2.
The growth rate of this species is medium: 9 to 10
feet in a 5 to 8 year period. This species reproduces mainly by seed,
in which birds and mammals are the medium of dispersal; the birds play
a major role in germination as they scarify the seeds after ingestion.
This species also sprouts from the roots. The seeds will not germinate
until after the second spring. This species is prone to rusts, blights,
powdery mildew, leaf minors, leaf spot, borers and scale3,4.
The growth rate of this species is rapid. This
species reproduces through dispersion of seeds. The flowers of this
species are fragrant, and so attracted animals for pollination. The
vectors for pollination are birds, butterflies and insects. This
species is also prone to rusts, blights, powdery mildew, leaf minors,
leaf spot, borers and scale2,4
Both A. laevis and A. arborea are short-lived, as previously mentioned.
This species is native to eastern North America. It is commonly found
distributed from northern Florida to Louisiana and Oklahoma, and
northward to Maine, New Brunswick, southwestern Quebec, southern
Ontario, northern Michigan, west to Alabama, southern Mississippi,
Louisiana, Texas (rare), Oklahoma, Kansas, Nebraska, Minnesota,
and the dry woodlands slopes and plateaus of Kentucky1,3,4.
This species is common throughout deciduous forests,
on the edges of woods and in ravines with moist hillsides. It is found
less frequently northeastward in the coniferous forest native from
Newfoundland to Georgia, Kentucky, Alabama, Minnesota, west to
Michigan, south to Pennsylvania and Kansas1,2.
This species was collected near the parking of the
Katherine Ordway Natural History Study Area in Inver Grove Heights,
Minnesota. The sample was chosen from the tree located on slightly
1. Rosendahl, C. O.,. (1955). Trees and shrubs of the upper midwest. Minneapolis: University of Minnesota Press.
2. Bernheim: Arboretum and Research Forest. 2010. http://www.bernheim.org/amelanchier_laevis.html
3. Bernheim: Arboretum and Research Forest. 2010. http://www.bernheim.org/amelanchier_arborea.html
4. United States Department of Agriculture: Natural Resources
Conservation Service. 2010.
5. Evergreen: Native Plant Database. 2010. http://nativeplants.evergreen.ca/search/view-plant.php?ID=00054
Compiled by Cynthia Kunakom
Biodiversity & Evolution (BIOL 270) Professr Sarah Boyer.Spring 2010
Specimen collected at Macalester College’s Katherine Ordway Natural History Study Area on April 15, 2010