MEDICAL BOTANY - A.G. Serbin - 2003

SECTION 3. SYSTEMATICS

SUPERKINGDOM EUKARYOTA — EUCARYOTA. KINGDOM PLANTAE

DIVISION GYMNOSPERMAE — GYMNOSPERMAE

Class Gnetopsida

Representatives of this Class, also known as chlamydosperms, differ from other gymnosperms by A number of features:

✵ strobili-bearing shoots have a dichasial arrangement;

✵ vessels are present in the wood, while resin ducts are absent;

✵ leaves are reduced to membranous scales and arranged oppositely;

✵ male and female sporophylls are surrounded by perianth-like integuments;

✵ gametophytes are strongly reduced;

✵ the sexual process resembles the double Fertilization of angiosperms;

✵ There is a single ovule, and the plant embryo has two cotyledons.

The class includes three monotypic orders and three families. Let us examine the genus Ephedra, belonging to the family Ephedraceae.

Family Ephedraceae

Genus Ephedra — Ephedra. Includes trees up to 8 m tall, shrubs, subshrubs, and lianas inhabiting deserts, semi-deserts, and stony slopes. Leaves are small, usually membranous-scarious and early deciduous. The assimilation function is performed by twiggy, green, jointed, ribbed shoots that branch in whorls. Male and female cones are arranged in groups of 2 — 4 at the stem nodes. Upon seed maturation, the outer cone integument

becomes woody, while the cover scales turn succulent, bright red, or yellow (the cone resembles a berry or a drupe).

In Central Asia, the Upper Tien Shan, and Kazakhstan grows Ephedra equisetina. Its shoots contain ephedrine and pseudoephedrine, which are valuable Alkaloids for medicine, as well as Tannins. In the Forest-Steppe and Steppe zones of Ukraine, in the Crimea, along stony maritime slopes, and on steppe sands grows Ephedra distachya (Fig. 3.98). This is a dioecious subshrub 5 — 15 cm high, with a rhizome and yellowish-green stems that are usually twisted at the top. Leaves are reduced to reddish membranes. Microsporangia develop on a special stalk called an antherophore. Female cones sit in groups at the nodes of oppositely arranged branches and bear several pairs of opposite cover scales. Mature cones are globose, 6 — 7 mm in diameter, succulent, red, and single-seeded. Seeds are light brown, lanceolate, flat on the ventral side and convex on the dorsal side, longitudinally wrinkled, and keeled. The inner seed coat is membranous, while the outer one is hard and stony.

Fig. 3.98. Ephedra distachya

Ephedrine stimulates the Central Nervous system and the respiratory center, causes peripheral vasoconstriction, stimulates Cardiac Activity, raises Blood pressure, inhibits intestinal peristalsis, relieves smooth Muscle spasms, and increases blood sugar levels. It is recommended for Bronchitis, whooping cough, Bronchial Asthma, urticaria, allergic conditions, and other diseases. It must be taken under medical supervision! A honey-flavored jam is made from the cone-berries.