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).