Plant Families II


Solanaceae.  Nightshade Family


1.     Plants are either herbs or shrubs.

2.     Leaves are usually simple and alternate.

3.     Flowers are actinomorphic and perfect.

4.     Calyx is of 5 sepals, fused, and in some genera, like Physalis, the calyx is persistent and accrescent; that is, it grows along with the developing fruit and encloses it. Remember the “Chinese lantern” fruit of Physalis.

5.     Corolla is of 5 petals and they are also fused. Some genera (Solanum and Physalis) have a rotate corolla, with a short corolla tube and broad, flaring corolla lobes. Other genera (Nicotiana) have a more funnelform corolla, with a long corolla tube and shallowly lobed corolla tips.

6.     Some genera have a hypogynous disk, as the red-orange disk at the base of the corolla of Nicotiana.

7.     Five epipetalous stamens

8.     Fruit is either a berry (Solanum, Physalis) or a capsule (Nicotiana).

9.     Major economic (culinary) plants of the family include: Solanum (potato, eggplant), Lycopersicon (tomato), Physalis (tomatillo), Capsicum (Sweet and hot peppers).

10. Major drug/poisonous plants of the family include: Nicotiana (tobacco), Datura (Jimson-weed), Atropa (belladonna and atropine), Mandragora (mandrake), and Hyoscyamus (henbane).


Lamiaceae (Labiatea) Mint Family


1.     Herbs or shrubs, often aromatic.

2.     Stems and twigs often quadrangular (4-sided)

3.     Leaves are opposite or whorled.

4.     Inflorescencs are often a pair of compressed cymes, forming a pagoda-like verticil along the floral axis.

5.     Flowers are often zygomorphic, 2-lipped (bilabiate).

6.     Both calyx and corolla may be bilabiate; when corolla is bilabiate the upper lip usually has 2 lobes, and the lower lip 3 lobes.

7.     Stamens are epipetalous. Some genera (Salvia) have only 2 stamens; others have 4. When there are 4 stamens, they are often arranged didynamously (2 + 2 arrangement , with each pair of stamens of unequal size).

8.     The ovary is 4-lobed, and the fruit that develops are 4 nutlets. (It is this feature that makes Lamiaceae similar to Boraginaceae).

9.     Lamiaceae is also very similar to Verbenaceae (Verbena and Lantana), in that both have quadrangular stems, opposite leaves, and are aromatic. Verbenaceae doesn’t have the 4 nutlets or the gynobasic style that members of Lamiaceae have.

10. Some economic members of this family include: Salvia (sage), Rosemarinus (rosemary), Mentha (mint), Marubium (horehound), Ocimum (basil), Origanum (oregano), Lavandula (lavender), Hedeoma (pennyroyal), Hyssopus (hyssop), Tectona (teak).


Polygonaceae.  Buckwheat Family


1.     Herbs or shrubs.

2.     Stems often with swollen nodes.

3.     Leaves are simple and alternate. Several genera (Polygonum) have stipule (below the leaves) that are joined together to form a sheath (ochrea) around the node.

4.     Flowers are small, incomplete, usually perfect. They may be borne in racemes or panicles, but if the ochrea ia absent, the flowers are usually borne in an involucre (ring of bracts). Likewise, where there is an involucre, there will be no ochrea.

5.     Calyx of 3 or 6 sepals.

6.     Corolla absent.

7.     Stamens either 6 or 9.

8.     Pistil is compound, usually tricarpellate (but may have 2-4 carpels). One style with 2-4, often 3, stigmas.

9.     Fruit is a 3-angled achene.

10. This is one of the few dicotyledenous families to have a 3-6 arrangement. This arrangement is usually expressed in the monocots (grasses, palms, orchids).