BIOL350 Lecture Notes - Lecture 2: Prunus, Aesculin, Acer Saccharinum
11 Oct 2017
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BIOL 350 Lecture 2-3 Select Trees & Shrubs of Ontario
[Supplementary text to aid with identification]
Source of taxonomic information: Kershaw, L. J. 2001. Trees of Ontario, including tall shrubs. Lone Pine
Publishing. ISBN 13: 978-1-55105-274-8.
Slide 4. Key features to Identify Trees & Shrubs
A. Conifers vs. Deciduous plants:
Conifers (or gymnosperms, or softwoods) produce cones rather than flowers and fruits. They produce
needle-like leaves and most are evergreen.
Deciduous (or angiosperms, or hardwoods) produce leaves with broad, flat blades. They produce
flowers with ovules (immature seeds) protected by ovaries, which eventually develop into fruits.
Slide 5. Key features to Identify Trees & Shrubs
B. Branching in deciduous plants (alternate vs. opposite):
Alternate branching: one leaf or branch at each node.
Opposite branching: two leaves or branches at each node.
Slide 6. Main leaf types
Simple, opposite leaves
Simple, alternate leaves
Palmate, opposite leaves
Palmate, alternate leaves
Compound, opposite leaves
Compound, alternate leaves
Needle-like leaves
Slide 10. Note
Note: This lecture presents many tree and tall shrub species common in Ontario, but the one listed on
this slide are not readily found on campus for the Tree ID Tour (Tutorial 1). Consequently, they will not
appear on the tutorial tree ID test; you will only be responsible for the 29 species we visit during Tutorial
2
1. However, the species listed below are important in Ontario from either an ecological or economic
perspective, and consequently you should be at least familiar with them.
horsetails (Equisetum)
red pine (Pinus resinosa)
Scots pine (Pinus sylvestris)
jack pine (Pinus banksiana)
black spruce (Picea mariana)
eastern hemlock (Tsuga canadensis)
tag alder (Alnus sp.)
bitternut hickory (Carya cordiformis)
white oak (Quercus alba)
chokecherry (Prunus virginiana)
black elderberry (Sambucus nigra)
Slide 11. Important Note for Tutorial 1 – Tree & Shrub Identification
Runs Fridays Sept. 22nd (TUT 103-104) & 29th (TUT 101-102)
Meet at The Link (between B1 & ESC), on the side towards Dana Porter library (the large planter
with the Ohio Buckeye and Honey Locust trees.
Involves walking outdoors around campus (rain or shine, hot or cold!!).
Dress appropriately (raingear if raining, avoid high-heels, etc.).
Slide 12. Pioneer species - Goldenrods (Solidago)
Goldenrods are one of eastern North America's most common wildflowers. In much of eastern Canada
and the northeastern United States, old fields are converted to fields of gold when the goldenrod
blooms in late summer.
One common misconception about goldenrods is that they are a common cause of hay fever. This is
not the case. Goldenrod is an insect-pollinated plant that produces very large and sticky pollen grains.
This feature makes sure insects come to feed on the pollen and that some gets stuck to the insect's
body. This ensures that some of the pollen gets carried to other goldenrods, allowing cross-pollination.
Because goldenrod pollen is so large, it doesn't get carried very far on the wind.
Goldenrods are clonal plants which spread by both specialized underground stems called rhizomes and
by seeds. Because of this vegetative growth through rhizomes, goldenrods form clumps of stems which
are all genetically identical (i.e., clones).
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Slide 13. Horsetail (Equisetum)
In the plant world, horsetails are most closely related to ferns. Like the ferns, they do not produce seed,
but rather reproduce sexually through the formation of spores. Short-lived, fertile shoots (2-12” tall) are
produced in the spring and are topped with a spore-bearing cone. These stems are jointed and yellowish
in color.
The hollow, jointed, unbranched stems of horsetail are the plant structure most people are familiar
with.
The leaves of horsetail are reduced to small scales at stem joints, and thus the stem is the primary
photosynthetic organ.
Horsetail stems contain high concentrations of silica and were once used to scour and clean various
surfaces – hence the common name “scouring rush”.
Spores are relatively unimportant in the spread of horsetails. Horsetail produces an extensive
underground rhizome system that can reach depths of four feet or more. Patches of equisetum expand
radially as the rhizomes extend outward from the patch center. In the absence of soil disturbance that
moves rhizome pieces, lateral spread of horsetail is relatively slow.
Horsetail is most commonly found in poorly drained areas, such as roadsides, wetlands and drainage
ditches. The preference for wet areas is due to a requirement for a moist environment during
reproduction with spores. However, horsetail may move into well-drained soils through vegetative
reproduction.
[Note: below, bold text identifies key distinguishing features]
Slide 16. Species Common in Secondary Communities - Chokecherry (Prunus virginiana)
Size & Shape: Trees or tall shrubs 4-10 m tall, often forming thickets; crowns rounded
Trunks: Often twisted or inclined, 5-10 cm in diameter; bark dark grey-brown, smooth or finely scaly,
with prominent lenticels; wood light brown, fine-grained, hard, heavy
Branches: Slender, ascending. Twigs strong smelling when crushed
Leaves: Alternate, simple, deciduous; usually widest at or above midleaf, abruptly sharp-pointed, 4-12
cm long, edged with small, slender, sharp teeth.
Flower: small, white, saucer-shaped, on 5-8 mm stalks. Flowers in cylindrical, 5-15 cm long clusters of
10-25 hanging from the tips of short new leafy shoots.
Document Summary
Biol 350 lecture 2-3 select trees & shrubs of ontario. Key features to identify trees & shrubs: conifers vs. deciduous plants: Conifers (or gymnosperms, or softwoods) produce cones rather than flowers and fruits. They produce needle-like leaves and most are evergreen. Deciduous (or angiosperms, or hardwoods) produce leaves with broad, flat blades. They produce flowers with ovules (immature seeds) protected by ovaries, which eventually develop into fruits. Key features to identify trees & shrubs: branching in deciduous plants (alternate vs. opposite): Alternate branching: one leaf or branch at each node. Opposite branching: two leaves or branches at each node. Note: this lecture presents many tree and tall shrub species common in ontario, but the one listed on this slide are not readily found on campus for the tree id tour (tutorial 1). Consequently, they will not appear on the tutorial tree id test; you will only be responsible for the 29 species we visit during tutorial.
