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College of Arts & Sciences

Use the guides below to identify Vegetative Characters used to describe the vegetative parts of plants!

Growth Form

Herb

-no woody tissue

Shrub

–woody, several stems from the base, less than about 25' tall

Tree

–woody, usually one main stem, usually more than 25 ' tall

Vine

–woody or herbaceous, stem climbing or twining

Simple & Compound Leaves

Simple

-the blade is all in one piece, though it may be lobed, toothed, etc.

Compound

–the blade is divided  all the way to the midrib (rachis) into two or more pieces.

Once pinnately compound

–leaflets arranged along one undivided main axis.

Compound

–the blade is divided  all the way to the midrib (rachis) into two or more pieces.

Twice pinnately compound

–main axis (rachis) with two or more branches and the leaflets arranged along the branches. The branch divisions are primary leaflets and the ultimate divisions are secondary leaflets.

Compound

–the blade is divided  all the way to the midrib (rachis) into two or more pieces.

Palmately compound

–leaflets all arising from one point at the base of the leaf.

Leaf Arrangement

Alternate

-leaves arranged one per node

Opposite

–leaves arranged two per node

Whorled

–leaves arranged two or more per node

Fascicled

-leaves grouped in small, tight bundles, eg., pine needles bundled into clusters of 2 or 3

Leaf Shapes

Ovate

-egg-shaped with the larger end at the bottom

Elliptic

-shaped like an ellipse, tapered at both ends and with curved sides

Oblong

-tapered to both ends, but with the sides more or less parallel

Lanceolate

-shaped like the tip of a lance, broadest at the base and tapered to a long point

Linear

-very long and thin, with the sides parallel

Orbicular-

nearly circular in outline

Cordate

-heart-shaped with the wide part at the bottom

Sagittate

-with two basal lobes that point backwards (toward the petiole)

Terete

-circular in cross-section. (The example shown is from a succulent plant)

Venation

Pinnate

-with a main midvein and secondary veins arising from it at intervals

Palmate

-with the main veins all arising from one point at the base of the leaf.

Parallel

-with all the main veins parallel (usually also parallel to the sides of the leaf.)

Dichotomous

-with each vein branching in two again and again (e.g. Ginkgo)

Lobing

Pinnately Lobed

-with the lobes arising along the length of the mid-line of the leaf.

Palmately Lobed

-with the lobes all arising from one point at the base of the leaf

Margins

Entire

-smooth, with no teeth or lobes

Serrate

-with sharp, forward-pointing teeth

Crenate-

with low, rounded scallop-like teeth

Undulate

-waving up and down

Spinose

-with stiff points

Parts of Leaf & Node

Petiole

-the stalk of a leaf; a leaf without a petiole is sessile

Blade

–the flat, expanded portion of the leaf

Stipule

flat, often leaf-like flap below a leaf. Not all leaves have stipules. Stipules can be highly modified into tendrils, spines, scales, etc

Axillary Bud

-the bud in the axil–the angle between the leaf and the stem.

Helpful Hint

: Remember to look for stipules below the petiole and an axillary bud above the petiole.

Stem Anatomy

Bud

–A compressed, undeveloped shoot. Buds may be lateral or terminal.

Node

–point on the stem where leaf or bud is borne. The space between two nodes is an internode

Leaf scar

–mark left on the stem where a leaf was attached

Pith

–the spongey tissue in the center of a stem or twig. Pith can be solid, chambered, or diaphragmmed

Lenticel

–a “breathing pore” in the skin or bark of a stem.

Stem Modifications

Tuber

–underground stem enlarged for storage of food–has nodes (unlike tuberous root)

Rhizome

–underground stem, often has buds which sprout to form new shoots

Stolon

–aboveground stem, has buds which sprout to form new shoots

Bulb

–underground stem with fleshy leaves which store food, e.g. onion

Corm

–solid, fleshy underground stem with papery leaves, e.g. Gladiolus, water chestnut

Roots

Tap root

–main root enlarging and growing downward

Fibrous roots

–thin, thread-like roots, usually without a primary root present

Aerial root

-adventitious root produced above ground, often for climbing

Tuberous root

–root enlarged for storage of food reserves, eg.

sweet potato

Armature

Thorns

-modified stems; have stem-like vasculature (e.g. Honey Locust)

Spines

–modified leaves, stipules, or bud scales (e.g. Cactus)

Prickles

-outgrowths of the epidermis, can be easily snapped off (e.g. Dewberry or Rose)

Texture

Succulent

–swollen and juicy.  Eg., cactus stems
and leaves of some plants.

Coriaceous

–stiff & leathery

Herbaceous

-thin and leaf-like (may be applied to many differnt sorts of parts, such as sepals, etc.)

Membranous

-thin and flexible, like a membrane. (In this photo, the bracts below the flowers)

Climbing Plants

Twining

-the stem wraps around an object for support (e.g. Morning Glory)

Tendrils

–modified shoots, petioles, leaves or stipules coil around the support (e.g. Vetch)

Aerial Roots

-small roots, often with sucker-like tips (e.g. Virginia Creeper or Poison Ivy)

Duration

Annual

-plant which lives for one year or season, reproduces, and then dies

Biennial

-plant which lives for two years or seasons, reproduces, and then dies

Perennial

-plant which lives for several to many years or seasons. Perennials may be woody, with stems that persist aboveground over the winter, or they may be herbaceous, with stems that die back to the ground each year.

Evergreen

-having leaves which persist for two or more seasons. Broadleaf evergreens usually have thick, leathery leaves.

Deciduous

-having leaves which die and fall in the cold or the dry season.