Achene – A type of fruit that has a seed-like appearance due the hard case that tightly encloses the single seed inside. The seeds do not open at maturity. For example, the seeds on strawberries are actually an aggregate of achenes. Note that a samara (below) is a winged achene.

Acuminate – The tip of the leaf elongates and tapers inwards to a very long, fine point. For example, white willow and some eucalyptus leaves.

Acute – A general term for any leaf tip or base that is less than a 90° angle.

Adventitious roots – Roots that sprout from elsewhere on the plant, not from the root system. Adventitious roots may sprout from stem nodes that are touching the ground. For example, strawberries, ivy, and strangler figs.

Aggregate fruit – A fruit that develops from a single flower with more than one ovary, where the ovaries join together. Examples are strawberries and raspberries, which are actually a collection of small fruits.

Alternate leaves – The leaves are staggered along the stem or rachis, alternating from the left to right side of the branch. For example, red alder, beech and sage leaves.

Anther – The enlarged tip or sack at the end of the stamen that produces the pollen. It forms part of the male reproductive organ of the flower.

Axil – The point where the leaf, stalk or stem meets the branch, on the upper side.

Axillary – A general term used to describe any buds, stalks, leaves and thorns that grow in the axil of a branch.

Basal (leaf) – Leaves that grow from a single point radiating from the base, at ground level, usually arranged in a rosette. For example, dandelion and thistle leaves.

Biannual – A plant that flowers and fruits twice a year (not common).

Biennial – A plant that takes 2 years to flower, set seed and die. For example, parsley and common mullein.

Bracts – Modified leaves that sit below the flower or inflorescence. They may be a different color, size or even texture to its regular leaves and flowers. Bougainvillea and poinsettia have enlarged, colorful bracts to attract pollinators instead of showy flowers.

Bulbils – Small bulbs that form in the axil of a branch that eventually fall to the ground to product a new plant. These bulbils are a clone of the parent plant. For example, lilies and some agave species.

Bulblets – Smaller, secondary bulbs that form near the underground parent bulb. This is often the primary mode for vegetative reproduction for many bulb species.

Calyx – A collective term for all of the sepals around the base of each flower. Sometimes the sepals are fused into a calyx. The calyx is often green but may be a variety of colors.

Carpel – The female reproductive organ that contains the ovary, style, and stigma. Otherwise referred to as a pistil.

Catkins – Flowers that have an inflorescence either without petals or with inconspicuous ones. Catkins are made up of unisexual flowers. For example, alder, willow, beech, and birch tree flowers.

Cladodes – Leaf-like structures that are modified, flattened branches that photosynthesize. The shape varies greatly; thick and broad, thin blades or small scales. For example, prickly pear, butchers’ broom, and asparagus shoots.

Clasping (leaf attachment) – The leaf attaches directly to the stem and wraps around it slightly to clasp it. For example, sow thistle stem leaves.

Compound flower – Multiple flowers or florets are arranged into an inflorescence. The structure of the compound flower may be in a spike, a raceme, a cyme, an umbel, a panicle or a catkin.

Compound leaf – The leaf is divided into smaller leaflets that are attached via a modified stem called a rachis. For example, clover, Oregon grape, ferns, acacia and ash tree leaves.

Cordate base – The base of the leaf is heart shaped. For example, violet and cottonwood leaves.

Corolla – The collective term for all of the petals on a single flower. The corolla is usually the showy, colorful part of the flower.

Creeping habit – A plant that spreads horizontally along the ground and hangs down over features. For example, strawberry plants and creeping thyme.

Crenate (leaf) – The leaf margin is softly rounded into numerous lobes. For example, ground ivy, stevia and ragwort leaves.

Cuspidate (leaf) – The leaf tip suddenly tapers to a short, obvious point. For example, holly and cherry leaves.

Cyme – A multibranched inflorescence that has the oldest flower growing from the end of the stem or middle of the inflorescence. The multiple branches are arranged alternately along the stem. For example, red maids, onions, tomatoes, elderberry and yarrow flowers.

Deciduous – Any tree, shrub or vine that loses its leaves every autumn and re-shoots in spring in temperate areas. For example, oak, birch, temperate fruit trees, and blackberry.

Dicot – All plants that emerge from their seed as a pair of leaves. All trees, shrubs, and herbs are dicots.

Drupe – A thin skinned fruit with a single, hard stone, nut or pit inside. For example, stone fruit such as peaches, cherries, olives, and mangos.

Drupelets – A cluster of small drupes, each with a single seed inside that forms a berry. For example, blackberry, mulberry, and raspberry fruit.

Elliptic (leaf) – The leaf is shaped like a stretched football, being pointed at both ends with the broadest point is in the middle. For example, beech and rhododendron leaves.

Emarginate (leaf) – The leaf tip is rounded on both sides of the central vein, forming an “m” shape or a notch at the leaf tip. For example, European alder have slightly emarginated leaves, whereas gingko have heavily emarginated leaves.

Entire (leaf) – The leaf margin is completely smooth and featureless. For example, basil and lilac leaves.

Epiphyte – A plant that grows on another larger plant but is not attached to it. It gathers nutrients from the air, water and the debris that accumulates around it. For example, bromeliads, mosses, and orchids.

Filament – The long, thin stalks in the middle of the flower that are part of the male reproductive organs. At the tip of the filament is the anther and pollen.

Indusium – The thin membrane that covers the spore producing sporangia on the underside of fern leaves. These covers will be absent on older leaves.

Inflorescence – A general, collective term for all of the flowering parts, including the flowers, bracts, stalks and stem. It may be multi-branched and include multiple flowers or florets clustered together. For example, lilac, lavender, and dill flowers.

Lacerate (leaf) – The leaf looks heavily lacerated or even ripped. For example, monstera and thistle leaves.

Lanceolate (leaf) – The leaf is shaped like a lance or spear point. It’s narrow and pointed at the tip, but broader towards the base. For example, willow and eucalyptus leaves.

Lance-shaped – A general term to describe the shape of petals, leaves and other vegetative features that have a pointed tip but are broader towards the base, like a spear point.

Leaflet and terminal leaflet – Multiple, smaller leaflets make up a compound or pinnate leaf that are arranged on a single stem or rachis. A terminal leaflet is at the growing tip when there is an odd number of leaflets arranged along the stem. For example, elderberry and pin oak leaves have a terminal leaflet.

Lenticels – Pores found in the bark and roots of some trees and shrubs which allow for gas exchange. For example, wild cherry, alder, and birch bark as well as potato skins.

Linear (leaf) – The shape of the leaf is long and narrow, and doesn’t broaden in the middle. For example, Easter lily, grasses, flax, and yucca leaves.

Lithophyte – A plant that grows directly on or into the surface of bare rock or stone and gathers nutrients from the air and water. For example, lichens and Paphiopedilum orchids.

Lobe – A term to describe various plant parts (leaves, petals, sepals etc.) that have rounded tips or softly protruding features. Marginal teeth – Any vegetative part that has teeth along its outer margin. For example, birch leaves as well as chicory and dandelion petals.

Minute (leaf) – A tiny leaf. For example, baby tears, woolly thyme and Scottish moss.

Monocarpic – Plants that die soon after flowering and setting seed. They can live for a number of years but will only flower and set seed once in their lifetime. For example, century plants, some yuccas, and bamboo species.

Monocot – All plants that emerge from their seed as a single leaf blade. For example, grasses, sedges and reeds.

Mucronate – The tip of the leaf forms a small point, which is smaller than on a cuspidate leaf. For example,
hazel and crabapple leaves.

Nodding flowers – Flowers that hang downwards on long pedicels, towards the ground instead of being held erect. For example, nodding onion, lily, and bluebell flowers.

Obcordate (leaf) – The tip of the leaf is a rounded heart shape. For example, wood sorrel and clover leaves.

Oblanceolate – The reverse of a lanceolate leaf, where the tip of the leaf is rounded and slightly broader but narrows to a point at the base, where it connects to the petiole. For example, red chokeberry and some Euphorbia species.

Oblong leaf – The shape of the leaf is roughly oblong shaped, having parallel margins with rounded tips. For example, lily of the valley, dwarf umbrella trees, and banana leaves.

Obovate leaf – The reverse of an ovate leaf, where the broadest point is towards the top of the leaf. Obovate leaves are broader and shorter than lanceolate leaves. For example, white clover and horse chestnut leaves.

Obtuse (leaf) – Either the base or the tip is completely rounded. For example, kidney weed and many succulent leaves like the jade tree.

Opposite leaves – The leaves are arranged into pairs along the stem and sit directly opposite each other. For example, basil and ash leaves.

Orbicular (leaf) – The leaf is almost completely round and forms a disk. For example, nasturtiums, water lilies, and some geranium leaves.

Ovary – Bulb-like structures that contains the ovules inside. The ovary sits deep within the flower and receives pollen for fertilization to eventually produces the seed. It sits on top of the receptacle, usually surrounded by the calyx.

Ovate (leaf) – The widest point of the leaf is towards the base. For example, common lilac and honeysuckle tree leaves.

Ovule – Part of the female reproductive organ that contains the egg cells. The ovules are inside the ovary of the flower.

Palmate (leaves) – The leaf is deeply divided into multiple fronds that extend all the way to the midrib or stalk. For example, a palm or maple leaf.

Palmatifid – The leaf is shaped like a palm with fingers, being divided into a few fronds, but not as deeply as palmate leaves. For example, coriander and castor leaves.

Panicle – A loose forming cluster of florets where each flower hangs from its own stalk (pedicel) that is arranged along a raceme (single stem). For example, grasses, oats, and crabgrass flowers.

Pappus – The feathery hairs or bristles that are attached to some seeds. The pappus is technically a modified calyx and is usually used for wind dispersal of seeds. For example, grass, dandelion, thistle, and oleander seeds.

Pedicel – The individual flowers in an inflorescence are attached via a pedicel (flower stalk). When the flower
is fertilized, the pedicel becomes the stem of the fruit in some plants.

Peltate (leaf attachment) – The petiole (leaf stalk) is centrally attached to the underside of the leaf. For example, water lilies and nasturtium leaves.

Perennial – Any plant that lives longer than 2 years. For example, trees, shrubs, and many herbs and grasses.

Petiolate (leaf attachment) – The leaves are attached to the stem via a petiole (leaf stalk).

Perianth – The collective term for all of the petals (corolla) and sepals (calyx) of a flower. For example, an opening rose bud only has its perianth on display.

Perulate (buds) – New buds that are protected by scales or modified leaves along the stem or branch.

Petal – Usually the showy, colorful part of the flower. The petals help to attract pollinators. All of the individual petals make up the corolla.

Petiole – Another name for the leaf stalk. The petiole attaches the leaf to the stem and allows the leaf to twist towards the sun.

Pinnate leaves – A type of compound leaf. Smaller leaves or leaflets are closely arranged along a central leaf stalk called a rachis. For example, locusts, acacia, and fern leaves.

Pinnatifid – A leaf that is heavily divided, but not all the way down to the leaf midrib or central vein. For example, netted chain fern and resurrection fern.

Pistil – Otherwise referred to as the carpel or fused carpels, the pistil contains all of the female reproductive organs, including the ovary, style, and stigma.

Pistillate (flowers) – Flowers that only contain the female reproductive organs (the opposite of staminate flowers). For example, ginkgo, willow, holly, oak, cottonwood, and wild grape flowers.

Pollen tube – When male pollen lands on the female stigma, a tube is formed inside the style to transport the pollen down to the ovaries for fertilization.

Raceme – Multiple flowers or florets are arranged along a single stem, but unlike a flower spike, each individual flower on a raceme has its own pedicel (flower stalk). The oldest flowers are at the bottom of the raceme. For example, mustard, radish, snapdragon, indigo, hydrangeas, and foxglove flowers.

Rachis – On pinnate leaves, the rachis is the central stalk that the leaflets are attached to.

Receptacle (part of flower) – The upper part of the pedicel that holds the calyx and petals. The female pistil usually sits on top of the receptacle.

Reniform leaf – The leaf is rounded at the top and heart shaped at the base where the petiole or stalk attaches. It’s roughly kidney shaped. For example, kidney weed and violet leaves.

Rhizome – A type of spreading, underground root system that sends out roots horizontally. They can produce new plants as a means of asexual reproduction. The new plants grow their own roots and foliage from the buds along the rhizome and the plant is able to spread. Rhizomes tend to be shallow rooted. For example, ginger, bamboo, cattail, Bermuda grass, and mint.

Rosette – Basal leaves that grow horizontally from a single point and tend to lay completely flat. For example, dandelion and flatweed.

Sagittate – The base of the leaf extends downwards to form an arrowhead or wedge shape. For example, elephant ears or taro leaves.

Samaras – A winged version of an achene fruit; a single seed held tightly within a hard case. For example, maple and tree of heaven seeds.

Saponins – The chemical compounds found in certain plants that can create a soapy foam when mixed with water. They are both water and fat soluble, so they have a wide number of uses; from soap making to stunning fish. For example, soapwort and soapbark tree are high in saponins.

Scorpioid cymes – An inflorescence that is shaped like a scorpion tail and unfolds as it matures. The oldest flower is at the base of the inflorescence where it joins the top of the stem and the flowers are arranged in a zig-zag or alternating pattern. For example, many species in the borage family.

Sepal – The individual sepals form a protective ring around the base of each petal to protect the reproductive organs and seeds. When a flower is budding, the sepals are closed tight to protect the developing flower. Serrate (leaf) – The leaf margin is like a saw blade, with each saw tip pointing towards the tip of the leaf. For example, apple, poplar, and stinging nettle leaves.

Sessile (leaf) – The leaf attaches directly onto the stem without a petiole (stalk). For example, trillium species, basket grass, and many succulents.

Sheathed (leaf attachment) – The leaf attaches via a tubular sheath that wraps around the stem. For example, grasses and bamboo.

Sorus (plural; Sori) – A cluster of tiny spore-producing sporangia that grow on the underside of fern leaves.

Spadix (plural; Spadices) – An inflorescence that is held vertically on a modified, fleshy spike and densely packed with minute flowers. The spadix is surrounded by the spathe. For example, calla lily and Anthurium species flowers.

Spathe – A modified, enlarged bract that resembles a sheath-like leaf or giant petal to attract pollinators to the spadix. For example, the white fleshy part of calla lily flowers is the spathe. Other arum species have different colored spathes.

Spatulate (leaf) – The leaf is shaped like a spatula, spoon or inverted teardrop, being broad and rounded at the tip and curving inwards towards the base. For example, water oak and spinach leaves.

Spike (flower arrangement) – Multiple flowers or florets are arranged vertically along the stem. The flowers don’t have pedicels (flower stalks), so are attached directly to the stem. For example, calla lily, sedges, and grasses such as barley and wheat.

Sporangia – The reproductive organs of a fern. Sporangia are small brown sacks that produce the spores.

Spore – Asexual reproduction in ferns is primarily through microscopic, wind dispersed spores that don’t require input from other reproductive cells or organs.

Stamen – The filament, anther and pollen all form the stamen, which is the entire male reproductive organ of the flower.

Staminate (flowers) – Flowers that only contain the male reproductive organs (the opposite of pistillate flowers). For example, ginkgo, willow, holly, oak, cottonwood, and wild grape flowers.

Stem (main stem vs lateral stem) – The main stem is the thickest and often the tallest stem on the plant. The
stems that branch off the main stem are called lateral stems.

Stigma – Part of the female reproductive organ that catches the pollen. The stigma is usually found in the center of the flower, at the top of a prominent style. It can be sticky, hairy or cup shaped to catch the male pollen. The pollen is sent down the pollen tube to the ovaries.

Stipe – An elongated, modified petiole (leaf stalk) that supports flowers, fruits or other structures in certain plants such as orchids and ferns.

Stipulate – Leaves that have stipules are called stipulate. Stipules can also grow into tendrils, spikes, thorns, scales, sheaths or leaves.

Stipule – A small pair of modified leaves that form at the base of the petiole, on the opposite side of the axil. For example, the base of hibiscus, gardenia, and rose’s compound leaves as well as the thorns of mesquite trees have stipules.

Stolon – A type of tendril that spreads horizontally along the surface of the ground and can produce new plants as a means of asexual reproduction. For example, strawberry and spider plants spread via stolons.

Style – The long, prominent female reproductive organ that is usually found in the middle of the flower. It connects the stigma to the ovaries when the pollen tube develops inside the style.

Tepal – When it is not possible to tell the difference between the sepals and the petals, the term tepal is used, especially when the sepals and petals are fused together. For example, magnolia, lily, and hellebore flowers.

Toothed leaf – The leaf margins have teeth that project outwards instead of towards the tip of the leaf. For example, thimbleberry, birch, chestnut, and elm leaves.

Truncate – The leaf or petal is squared at the tip or base. For example, the base of common green briar, mile-a minute vine, and tulip tree leaves.

Tuber vs mother tuber – A tuber is an annual, underground energy storage system for the roots, rhizomes or stolons. It uses the stored energy to reshoot every season and is also a means of asexual reproduction. A mother tuber is the original tuber that subsequent, younger ones have grown from. The mother tuber is usually darker in color. For example, potatoes, yams, cassava, daylily, and dahlia root systems.

Umbel – Multiple flowers are arranged into an umbrella shaped structure. Numerous pedicels grow from a single point at the top of the stem and each pedicel produces a single flower. Umbels can   be simple or compound. For example, queen Anne’s lace, carrot, onion, and wax flowers.

Undulate (leaf) – The leaf margins are broadly wavy. For example, some species of oak trees, bay tree, and taro have undulated leaves.

Winnow – The act of separating the grain or seed from the bracts and pedicels (also known as chaff) after threshing using a light breeze.

Medical Terminology List

Analgesic – To have pain-relieving properties.

Astringent – To cause the cells and tissues to tighten and contract.

Cholagogue – To cause an increase in the amount of bile being released by the liver and gall bladder.

Demulcent – Usually high in mucilage, a demulcent creates a protective barrier over the mucus membranes along the gastrointestinal tract.

Diaphoretic – To cause sweating.

Diuretic – To cause an increase in urine production, which subsequently reduces the amount of water and salts in the body.

Dysentery – A bacterial infection of the lower intestines and colon which causes diarrhea and stomach cramps.

Emetic – To cause vomiting.

Emollient – To have moisturizing and lubricating properties.

Expectorant – To soften phlegm and sputum to make it easier to cough up and expel.

Febrifuge – To reduce fever and high temperatures.

Pectoral – To treat discomfort, pain and illness around the chest and lungs.

Purgative – To have a laxative effect by loosening stools as well as lubricating bowel movements.

Rheumatism – A type of disease that causes pain, swelling, inflammation and loss of movement in the joints, tendons, ligaments, muscles and bones. Arthritis causes the same symptoms in joints.

Stomachic – To increase appetite and promote healthy digestion.

Vasodilator – To dilate or open the arteries, veins and other blood vessels, which increases blood circulation.

Vermifuge – To expel or kill intestinal worms and parasites.