The petiole is the small thin stalk that is attached to the stem and the leaf blade lamina. Foliage on trees and plants that is made up of simple leaves only have a single blade growing on the stalk. So, a simple leaf just has one blade on each petiole.
Simple leaves can grow in alternate arrangements or opposite arrangements on the stem. Examples of deciduous trees with simple leaves include maple trees, sycamore trees , elm trees , and oak trees. Compound leaf consists of several leaflets joined to a single stem. Compound leaves are when there are a number of leaflets growing on one leaf stalk petiole. You can think of this as a number of small leaves that grow together to form a complete leaf.
It can be tricky to know if the leaf you have in your hand is a simple leaf or compound leaf. If there is a node, then you have a simple leaf, whereas a lack of node indicates it is a compound leaf. Examples of trees with compound leaves include ash trees, walnut trees , hickory trees , and horse chestnut trees. There are a number of types of compound leaves, and knowing about them can help make tree identification easier.
Types of compound leaves. From left to right: pinnate leaves, palmate leaves and double pinnate leaves. Trees that have pinnate leaves mean that the leaflets on the compound leaf grow in each side along the length of the petiole like a feather arrangement.
Sometimes these types of leaves called pinnately compound leaves. Palmate leaves have a number of leaflets growing at the end of the leaf stalk. These compound leaves usually look like the shape of a hand with a palm and fingers. That is why they are called palmate leaves. Trees that grow palmate leaves include horse chestnut and buckeye trees. Trees with bipinnate leaves have leaves that resemble fern leaves. You will notice in pictures of double pinnate leaves that the compound leaves are made up of a number of secondary stems that have leaflets growing in an opposite arrangement.
Some examples of trees with bipinnate leaves are honey locust trees, the Texas redbud, and Kentucky Coffee trees. You can identify a tree by its leaf shape. From left to right: unlobed leaf, lobed leaf and toothed leaf.
One very important way to identify types of tree leaves is by the overall shape of the leaf around its edges. The edges of leaves create patterns that are often unique to the species of tree and help with identification. Later in the article, you will learn more about the specific shapes of entire leaves. These types of leaves can also be called unlobed leaves.
Lobed leaves can have rounded tips like the white oak leaf left or pointed tips like maple leaf right. The most easily identifiable type of tree leaf is the lobed variety. These leaf blades are made up of earlobe-like shapes, but they form a single leaf. The clefts or indentations between the lobes can be deep or shallow depending on the type of tree. The space or indentation between two lobes is called sinus. Some examples of trees with lobed leaves include oak trees and maple trees.
You will see in pictures the differences between the types of lobes these leaves have. Maple trees have pointed lobes, whereas white oak tree leaves have a rounded lobe shape. Leaves with a serrated edge or with tooth-like shapes around the margins are called toothed leaves. Depending on the species of tree, the toothed edges can be so fine that you have to look close to notice them.
Other types of toothed leaves can look like a steak knife. Examples of trees that grow toothed leave are chestnuts , elms, hazel trees, rowan, and ash trees. Although they may not look like leaves, coniferous evergreen trees such as pine, spruce, cedars, and fir trees have leaves. Evergreen coniferous trees leaves are generally made up of needle-like leaves that can be soft or hard. The types of conifers with single needles are fir trees, spruces, and cypress trees.
Pine trees have cluster needles. The other type of evergreen conifer leaf can be described as cluster or bundle needles. These grow like clumps of evergreen needles along the twigs of the tree. You can use the type of needle leaves to tell pines apart from fir trees because pines have cluster needles. We have looked at ways of identifying leaves by looking at the way they are arranged on the stem and their overall shape. Tree leaves come in all sorts and sizes, and knowing the shape of particular leaves can help to quickly identify the tree species.
Tree leaf chart: Leaf shape and arrangement. Image by Wikimedia Commons. Looking at the shape of the leaf is usually the first way people try to identify the species of tree.
The botanists at the Smithsonian collected the initial data sets of leaf species and the photography. Every leaf photograph that is uploaded is matched against a leaf-image library so that the best matches are ranked and noted for verification. It is complicated because " within a single species , leaves can have quite diverse shapes, while leaves from different species are sometimes quite similar, so one of the main technical challenges in using leaves to identify plant species has been to find effective representations of their shape, which capture their most important characteristics.
It's not perfect The leaf identification process needs work. You have to take a picture of the leaf against a white background, which is a bit awkward when you are marching around. That tree could come in handy right now for some Canadians. And for this TreeHugger, the snapshot part wouldn't work at all. However, there is a nice visual dictionary of leaf types which can be matched to names and descriptions if one has the patience to scroll through it.
There are photos and information about the tree's flowers, fruit, seeds and bark--giving the user a very full understanding of the species. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile.
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