| A | B |
|---|
| epidermis | transparent, most cells with no chloroplasts |
| cuticle | waxy layer of variable thickness |
| mesophyll | between upper and lower epidermis |
| palisade mesophyll | chlorenchyma in tightly packed rows close to the upper epidermis |
| spongy mesophyll | loosely packed chlorenchyma nearer lower epidermis |
| leaf abscission | all plants lose leaves |
| abscission zone | at base of petiole |
| bracts (floral leaves) | large, colorful leaves functionally act as petals; flowers usually inconspicuous (poinsettias, dogwoods) |
| spines | cacti and others – reduction in leaves reduces water loss and protects from predators |
| reproductive leaves | as in maternity plant, walking fern |
| “evergreens” | lose and replace their leaves continuously in small numbers |
| deciduous plants lose | and replace all leaves together in response to seasons |
| window leaves | cone-shaped leaves with a transparent tip; allows light into hollow interior, thus allowing some buried plant parts to have photosynthesis below ground |
| shade leaves | leaves in shady areas have larger surface area and are thinner compared to leaves that receive more direct light |
| carnivorous leaves | designed to capture animals (mainly insects) to provide a nutrient supplement (common in swampy areas with sandy soil and high amounts of sunlight, where nitrogen and/or phosphorous may be limiting – example: southeastern U.S.) |
| most vascular plants make either a taproot system (one main root with branches) | or fibrous root system (many roots of similar diameter); there are several modified root types |
| phloem | principle food conducting tissue – carbohydrates (sucrose mainly); also amino acids, hormones |
| vascular tissue | contains various dissolved minerals and ions |
