Lesson 38- Dicotyledonoous Plant Structure

1. Outline the wide diversity in the plant kingdom as exemplified by the structural differences between bryophytes, fillcinophytes, coniferophytes, and angiospermiophytes.

Bryophytes have no roots, only structures similar to root hairs called rhizoids. Mosses have simple leaves and stems. Liverworts consist of a falttened thallus.

Filicinophytes are also known as ferns which have roots, leaves and short non-woody stems. the leaves are usually curled up in a bud and are often pinnate-divided into pairs of leaflets.

Coniferophytes also known as conifers are shrubs or trees with roots, leaves, and woody stems. the leaves are often narrow with a thick waxy cuticle.

Angiosperms are also known as flowering plants. Flowering plants are very variable but usually have roots, leaves and stems. The stems of the flowering plants that develop into shrubs and trees are woody.

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4. The function of the leaf is to produce food through photosynthesis. The dermal tissues also known as the epidermis function to keep water from entering the plant, and it maintains water storage. The vascualr tisssue concists of the xylem, which replaces water that was lost through transpiration. The pholem found in the vascular tissues removes products ;eftover from photosynthesis after the plant has used necessary materials. The ground tissue functions to protect the plant, storage of water and glucose, and support.

5. Plants that are adapted to grow in very dry habitats are called xerophytes. The cactus is an example of a xerophyte. It grows iun deserts in Mexico and Arizona which shows xerophytic adaptations.

-Spines instead of leaves, to reduce transpiration

-Thick stems containing water storage tissue

-Very thick waxy cuticle covering the stem

-Very wide-spreading network of shallow roots to absorb water after rainfall.

6. Plants that are adapted to grow either submerged in water or floating on the surface are called hydrophytes. An example of a hydrophyte is the water lily.

-Air spaces in the leaft provide buoyancy

-Stomata in the upper epidermis of the leaf, which is in contact with the air but not in the lower epidermis.