Tree classifications Flashcards
Bark features include texture, color, and the presence of lenticels (or pores).
Tree bark may be smooth (Figure 2A), furrowed (Figure 2B), flaky (Figure 2C), or warty (Figure 2D). Furrowed bark has cracks and fissures, flaky bark tends to peel or flake off easily into thin layers, and warty bark has small nodules that look like warts.
Leaf characteristics such as their
persistence, structure, complexity, shape, venation, surface, smell, taste, and arrangement on the branch
Cherry tree leaf persistance
laurel cherry is evergreen and black cherry is deciduous.
Significance of twig growth and deciduous/evergreen determination
One way to determine leaf persistence is to look at older twig growth (previous seasons) vs. new twig growth (current season). On many plants, you can identify where new growth began by locating the terminal bud scar nearest the end of the twig (Figure 5). All growth between the end of the twig and its nearest terminal bud scar is new growth. If you only see leaves on this portion of the twig, you are probably looking at a deciduous species. This is because deciduous plants shed these leaves after the season is over. When the next season comes around, the plant puts out leaves on new twig growth. However, if you see leaves present (i.e. “persisting”) on an older portion of the twig, that plant is an evergreen species.
Leaf structure
Blade, a petiole, and sometimes stipules
Leaf structure detailed
The leaf blade is the expanded portion of the leaf, the petiole is the supporting stalk that connects the leaf blade to the branch, and stipules are small vegetative structures that form at the base of the petiole or on the twig.
Simple and Compound leaves
If a leaf has a single blade, it is simple (Figure 6); usually you can see a bud where the leaf meets the stem or branch. If the leaf has multiple blades attached to a common stalk or petiole, then it is compound and the individual blades are called leaflets.
Compound types
Compound leaves can be pinnately, bi-pinnately, trifoliolately, or palmately compound
Bud impact on simple/compound
You can determine if a leaf is simple or compound by looking for a bud at the base of the leaf. If you cannot find a bud below a leaf, you may be looking at a leaflet which is part of a compound leaf.
Complexity as filter
Leaf complexity is a great filter because most tree species have simple leaves. If your tree has compound leaves, then you can eliminate a large number of tree species that have simple leaves
Leaf Arrangement
Alternate, opposite, or whorled.
Arrangement details
Alternate arrangement is when one leaf is attached at each node and the leaves emerge in an alternating pattern on the twig (Figure 9A). Opposite arrangement is when leaves emerge paired on each side of the twig (Figure 9B). Whorled arrangement is when more than two leaves are found at the same node
Arrangement as filter
Many trees species have an alternate leaf arrangement, fewer species exhibit opposite or whorled leaf arrangement.
Leaf shapes
A long, slender pine needle is described as acicular (Figure 4A and Figure 10). Additional common leaf shapes are: deltate, elliptical, lanceolate, linear, obovate, and reniform
Environmental impact on leaf shape
if a tree is shaded by other trees growing near it, the leaves found near the top of the shaded tree may be very different from those found near the base of the same tree. In the shaded areas, larger leaves maximize the amount of surface area exposed to sunlight. Leaves that are exposed to full sunlight and wind (usually near the top of the tree) are usually smaller.
