Leaf and Vegetative Terminology

Question 1

Describe Alternate Leaves:

Answer 1

Leaves that grow singly, or take turns growing on each side of the stem. (*think footprints, spiral staircases, & in between)

Question 2

Describe Opposite Leaves:

Answer 2

Leaves that grow directly across the stem from each other.

Question 3

Describe Whorled Leaves:

Answer 3

Three or more leaves growing out of the same spot on the stem (like umbrella spines.)

Question 4

Can a plant have more than one leaf configuration? Name an example.

Answer 4

Uncommon, but yes. Wild yams’ leaves are whorled at the base, turn to opposite mid-vine, and finally alternate at the top of the stem.

Question 5

What is another word for compound leaf?

Answer 5

Divided

Question 6

Describe a Single Leaf:

Answer 6

Leaves that grow as a single entity, like lettuce

Question 7

Describe a Compound Leaf:

Answer 7

Leaves that divide into further segments (leaflets) at the midrib or petiole, like parsley or carrot.

Question 8

Describe Pinnately Compound Leaves:

Answer 8

Leaflets are arranged on either side of the centrally elongated axis. (eg. ash - Fraxinus spp., hickory - Carya spp., and sumac - Rhus spp.)

Question 9

Describe Bi-Pinnately Compound Leaves:

Answer 9

Doubly pinnate, or twice-compound, leaflets are further divided into even smaller segments. (eg, mimosa - Albizia julibrissin, and honey locust - Gleditsia triacanthos)

Question 10

Describe Tri-Pinnately Compound Leaves:

Answer 10

Triply pinnate, or thrice-compound, leaflets are further divided into smaller segments, which are in turn divided into even smaller segments. (eg, heavenly bamboo - Nandina domestica)

Question 11

Describe Palmately Compound Leaves:

Answer 11

Leaflets radiate from a central point, much like fingers on the palm of a hand. (eg, buckeye - Aesculus spp., and horse chestnut - A. spp.)

Question 12

What is the Bob Marley trick for telling the difference between leaves and leaflets?

Answer 12

“One bud, one leaf, lets get together and botanize…” True leaves have buds growing at their base on the stem, leaflets do not.

Question 13

Define Petiole

Answer 13

The leaf stalk - the conjoining point between midrib and the stem.

Question 14

What is a petiole-less leaf called?

Answer 14

A sessile (stalkless)

Question 15

Define Midrib

Answer 15

The central vein running up the center of the leaf.

Question 16

Define Blade

Answer 16

The broad, photosynthetic surface of the leaf.

Question 17

Define Margin

Answer 17

The edge, or border, of the leaf.

Question 18

What is a Node?

Answer 18

The part of the stem from which one or more leaves emerge.

Question 19

What is a Stipule?

Answer 19

Leafy appendage at the node; green outgrowths at the base of the petiole.

Question 20

What is a Lateral Bud?

Answer 20

A bud that rests in the node, between the petiole and the stem, as opposed to the tip of the branch.

Question 21

What are Basal Leaves?

Answer 21

Leaves that emerge from a central point in the earth rather than from a stem. (Leaves are clustered at the base of the stem and are often called the “basal rosette”)

Question 22

Define Lobed

Answer 22

A leaf with deeply indented margins (not toothed, though leaves can be both)

Question 23

Define Pubescent

Answer 23

Hairy.

Question 24

Define Glabrous

Answer 24

Hairless (smooth.)

Question 25

What type of Margin has a smooth edge?

Answer 25

Entire.

Question 26

What type of Margin has a saw-tooth with upward-pointing teeth (toward the leaf’s tip)

Answer 26

Serrated.

Question 27

What type of Margin has a saw-tooth with right-angled teeth?

Answer 27

Dentate

Question 28

What type of Margin has rounded, or scalloped, teeth?

Answer 28

Crenate.