Unit 4: Study of Angiospermic Families

Dicotyledonae Families

This section covers the vegetative and floral characteristics of representative Dicotyledonous families.

1. Ranunculaceae (Buttercup Family)

• Characters: Mostly annual or perennial herbs with acrid juice. Flowers are usually bisexual, actinomorphic, and often have numerous stamens and carpels arranged spirally.

2. Magnoliaceae (Magnolia Family)

• Characters: Trees or shrubs with large, showy, solitary flowers. Stamens and carpels are numerous and spirally arranged on a cone-like receptacle.

3. Brassicaceae (Mustard Family)

• Characters: Herbs with watery pungent juice. Flowers are cruciform (cross-shaped) with four petals. Fruit is a siliqua or silicula.

4. Malvaceae (Mallow Family)

• Characters: Herbs, shrubs, or trees often with mucilaginous sap. Flowers have monadelphous stamens forming a staminal tube around the style.

5. Fabaceae (Pea Family)

• Characters: Herbs, shrubs, or trees with root nodules. Flowers are zygomorphic with a papilionaceous corolla (standard, wings, and keel). Fruit is a legume.

6. Asteraceae (Sunflower Family)

• Characters: Inflorescence is a characteristic head or capitulum. Flowers (florets) are often of two types: ray and disc florets. Calyx is modified into a pappus.

7. Solanaceae (Potato Family)

• Characters: Mostly herbs or shrubs with alternate leaves. Flowers are actinomorphic with 5 fused petals and epipetalous stamens. Ovary is obliquely placed.

8. Lamiaceae (Mint Family)

• Characters: Aromatic herbs with quadrangular (square) stems. Leaves are opposite decussate. Inflorescence is often a verticillaster.

Monocotyledonae Families

This section covers representative families from the Monocotyledonae.

1. Orchidaceae (Orchid Family)

• Characters: Epiphytic or terrestrial herbs with highly specialized flowers. Flowers are zygomorphic with a distinctive labellum. Stamens and style are fused into a column. Pollen is often in masses called pollinia.

2. Musaceae (Banana Family)

• Characters: Large perennial herbs with a pseudostem formed by leaf sheaths. Inflorescence is a spadix with large, colorful bracts called spathes.

3. Poaceae (Grass Family)

• Characters: Annual or perennial grasses with cylindrical, hollow stems (culms). Leaves have a ligule at the junction of the blade and sheath. Inflorescence is a spikelet. Fruit is a caryopsis.