| Term | Definition |
|---|
| primordia | what leaves originate as in the buds |
| petiole | the stalk of a leaf |
| blade | the flattened...uh...body of the leaf that has a network of veins |
| stipule | a pair of leaf-like, scale-like or thorn-like appendages at the base of the petiole |
| sessile | when a leaf does not have a petiole |
| extipulate | when a leaf does not have a stipule |
| deciduous | leaves only live through one growing season |
| simple leaf | a leaf with a single blade |
| compound leaf | composed of a number of leaflets on a common stalk |
| pinnately compound leaf | has leaflets in pairs along an extension of the petiole called a "rachis" |
| palmately compound leaf | the leaflets are all attached to the same point at the end of a petiole |
| alternate | there is only one leaf per node |
| bipinnately compound leaf | (e.g. a fern) when the leaflets of a pinnately compound leaf are subdivided into smaller leaflets |
| opposite | 2 leaves may be attached to each node |
| venation | the arrangement of veins in the leaf blade |
| dichotomous leaf venation | (e.g. Ginkgo) a leaf in which the midvein is absent |
| pinnate venation | a leaf with veins branching out from a midvein |
| palmate venation | several primary veins fan out from the base of the blade |
| epidermis | a single layer of cells covering the entire surface of the leaf |
| cuticle | a waxy coating over the epidermis |
| mesophyll | ground tissue located between the 2 epidermal layers where most of photosynthesis takes place |
| palisade mesophyll | contains 80% of the leaf's chloroplasts |
| spongy mesophyll | loosely arranged layer of cells below the palisade mesophyll; stoma more common here than in palisade mesophyll |
| bundle sheath cells | surround vascular bundles and give the leaf structure (like a skeleton) |
| vein | vascular bundle+ bundle sheath cells |
| guard cells | control water loss by opening and closing stoma using turgor pressure |
| Stomata | pores on the leaf epidermis that allow transpiration and entry of carbon dioxide |
| shade leaves | tend to be larger to receive enough light in shady areas in order to perform photosynthesis |
| desert leaves | thick, leathery, fewer stomata--> all to minimize water loss |
| aquatic leaves | considerably less xylem than phloem; mesophyll not differentiated into palisade and spongy |
| tendrils | curl around more rigid objects to allow the plant to "climb" |
| pine needles | sunken stomata, thick cuticle, and a layer of thick walled celled beneath the epidermis |
| spines | LEAF common in desert plants; reduced surface area to minimize water loss in arid regions |
| thorns | modified STIPULE; protects plant from predators |
| prickle | neither leaf nor stipule but an outgrowth of the epidermis or cortex |
Combine with other sets
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