Botanical Description Definitions

While I took care not to get too technical in my descriptions of the common plants used in Part II of this book, you will need to have a working knowledge of the terminology if you want to be effective in researching wild plants.

It is very hard to accurately describe plants without the ability to understand basic botanical definitions.

Knowing the correct terms will also identify you as someone who cares about the subject, which is vital in gaining the support of your local expert. I used to teach radiological response, and I taught the same basic class to cops, volunteer firemen, foresters, nurses, and doctors. When describing the symptoms of acute radiation sickness to laymen, I could get away with saying something like, “If you vomit within an hour of exposure, you’re probably going to die,” but if I said the same thing (it did not matter if the statement was accurate) to a doctor, he or she would immediately label me as a novice or someone without knowledge. It would be different if I used the more technically accurate “Emesis within one hour of acute exposure is a positive sign that a lethal dose of radiation was received.” It is the same with botany as it is in any other professional field: correct terms are more accurate and will yield a better result when talking among those in the field.

Here are some common terms organized into groups based upon stem, leaf, and flowers.

Stem Parts:

The term stem refers to the structure that provides support to the plant. It acts as both the skeleton and the circulatory system and connects the roots to the leaves and flowers. There can be either a single stem originating from the roots with lateral stems growing from it, many different stems coming out from the roots, or a combination of the two. Where there is just one stem coming from the roots of a woody perennial (tree), it is known as a “trunk.”

Branch/lateral growth/side shoot: These different terms are used to describe stems that come out of the main stem. In general, they are slightly slimmer than the main stem or trunk of the plant.

Node: The node is the part of a plant stem from which one or more leaves emerge. Nodes often form a slight swelling or knob.

Internode: An internode is the area of a stem between two nodes.

Bud: A bud is an undeveloped or embryonic shoot. Buds most often occur at the tip of the stem or at the connection between leaf and stem.

Stipule: Stipules are small leaf-like appendages to a leaf, which are typically found in pairs at the base of the leaf stalk. Stipules come in a variety of forms, but not every plant has stipules.

Leaf Parts

Leaves grow out of nodes and are the organ of a plant that produces food. Oxygen and moisture is released from the leaf.

Axil: The axil is the connection between the leaf or leaf stem (petiole) and the stem or branch that supports the leaf.

Blade: The broad thin part of a leaf apart from the stalk is called the leaf blade (this may often be called a “lamina”).

Petiole: A petiole is the stalk-like portion of a plant that joins a leaf to a stem. It is generally flexible so the leaf can move in the wind, and some petioles will turn to orientate the lead blade toward the sun.

Sessile: Sessile is a term that describes a leaf that grows directly out of a stem without the benefit of a petiole.

Stipules: The stipules are two small flaps that grow at the base of the petiole of some plants. Some stipules, such as those of willows and certain cherry trees, produce substances that prevent insects from attacking the developing leaf.

Leaf Types

Leaves take on many shapes and are a vital part of plant identification. Most plant identification guides use these terms so that positive identification can be made:

Simple: Simple leaves are not divided or branched. Oaks, maples, and most deciduous tress have simple leaves of one leaf blade attached to a single petiole.

Compound: Compound leaves consist of two or more simple parts or individuals in combination. The blades of a compound leaf are fully subdivided into leaflets. A clover is an example of compound leaf, as is the black walnut.

Leaf Arrangements

Different terms are usually used to describe the arrangement of leaves on the stem:

Alternate: The leaves are placed alternately on the two sides of the stem. There will be only one leaf per node.

Opposite: In an opposite arrangement, there are two leaves per node. The leaves grow in opposed pairs, one on each side of the stem.

Whorled: A whorled arrangement is a set of leaves, flowers, or branches springing from the stem at the same level and encircling it. There are three or more leaves per node.

Spiral: In a spiral arrangement, there is one leaf per node, and it will generally corkscrew around the stem.

Flower Parts

Flowers are responsible for plant reproduction. This is where the seed, nut, berry, or drupe is formed. Flowers are very distinctive, and when present, greatly assist in positive plant identification.

Pedicel/peduncle: This is the stalk that supports the flower. Where this is a solitary flower it is called a peduncle. Where there is a grouping of flowers, each flower is attached to a stalk called a pedicel. Pedicels are then attached to a peduncle, which attaches the group of flowers and pedicels to the plant.

Receptacle: The receptacle supports all parts of the flower and attaches them to the pedicel/peduncle.

Sepal: The sepals are small, petal-like structures that sit below the petals and often form the covering of the flower when it is in bud form. They are often green and relatively thick. Collectively, these form the calyx.

Petals: Petals are the larger, usually colorful structures, which surround the fertile parts of the flower. When the petals are brightly colored, it is usually to attract bees and other pollinators to the flower. Collectively, the petals form the corolla.

Tepal: Where the sepals and petals are fused into one structure it is called a tepal. In reality a tepaled flower just looks like petals without sepals below them. Tulips are a common example of a plant with tepals.

Anther: The anther is the organ that produces the pollen sacs that will release pollen to fertilize the female ovule.

Filament: The filament is the stalk that supports the anthers and holds them at the right height to maximize opportunities for pollination.

Ovary: The ovary is the female portion of the flower that contains the ovule.

Ovule: The ovule contains the egg cells that will be fertilized by the male pollen. The ovule eventually develops into a seed and the ovary into a fruit.

Style: The style is the long structure that reaches from the ovary to the stigma. The pollen landing on the stigma must travel through the style to reach the ovary.

Stigma: The stigma is covered with a sticky substance that the pollen sticks to and feeds from before traveling down the style to fertilize the egg cell in the ovule.

Types of Fruit

There are many different end results to plant fertilization. All are developed to ensure that seeds become new plants. Fruits are divided into either fleshy fruits or dry fruits.

Fleshy fruits are further subdivided by whether the fruit is formed by a single flower or a group of flowers. They can have one seed or several seeds.

Berry, drupe, aggregation of drupes, pome, and hesperidium are types of fleshy fruits formed from a single flower, while sorosis, syconium, and coenocarpium are formed from a group of flowers.

Dry fruits are divided by whether or not the seeds are contained in a seedpod of some sort, or not. Seeds with seedpods are classified as dehiscent, while those without are called indehiscent.

Dry dehiscent fruits are follicle, legume, silique, and capsule.

Dry indehiscent fruits are achene, nut, samara, caryopsis.

Knowing the type of fruit a plant has might help you to identify it and might also help you to know when the seeds are ready to harvest.

Berry: A single fleshy fruit without a stone, usually containing a number of seeds. Tomatoes are an example of a berry.

Drupe: A single fleshy fruit with a hard stone, which contains the single seed. A cherry or a peach is an example of a drupe.

Aggregation of Drupes: A fleshy fruit, made up of many drupes but formed from a single flower, each drupe containing one seed. A blackberry is an example of this.

Pome: A fleshy fruit with a thin skin that is not formed from the ovary. The seeds are contained in chambers in the center of the fruit. Apples are pomes.

Hesperidium: A berry with a tough, aromatic rind. Oranges, lemons, and limes are good examples of hesperidiums.

Pseudocarp: A pseudocarp is a false fruit, because it does not contain the seeds. The seeds are achenes, on the outside of a fleshy fruit. Strawberries are the best example of pseudocarps.

Follicle: A dry dehiscent fruit that splits on one side only. It may contain one or many seeds. The milkweed described in Part II is an example of a follicle.

Legume: A dry dehiscent pod that splits on two sides. Peas and peanuts are commonly known legumes.

Silique: A dry dehiscent fruit that is long and thin, splits down the two long sides, and has a papery membrane (the septum) between the two halves. Cabbages and radishes are both silique seeds.

A silique that is less than twice as long and broad is called a silicula.

Capsule: A dry fruit which splits open to release the seeds. It is the most common fruit type. Cotton, horse Chestnut, jimson weed, and witch hazel are all well-known examples of capsules.

Achene: A single-seeded dry indehiscent fruit in which the seed coat is not part of the fruit coat. A sunflower has achene seeds.

Nut: A large, single, hardened achene. Chestnuts, acorns, hickory, and walnuts are all common nuts.

Caryopsis: A simple dry indehiscent fruit, like an achene, but with the seed coat fused with the fruit coat. Many caryopsis have been domesticated for food usage—corn, oats, rice, rye, and wheat are all examples of this.

Samara: An independent, dry indehiscent fruit that has part of the fruit wall extended to form a wing. Maples are examples of this type of seed.