COMMENTS ON EPHEDRA
Habit
Straggling plant:
Ephedra is a highly developed gymnosperm confined to temperate and subtropical regions of the globe. It exhibits straggling or climbing habits. It is widely cultivated for the extraction of valuable dry Ephedrine drugs.
Vegetative structure
Sporophytic plant:
The sporophytic plant is a small green woody much branched jointed fistula shrub reaching the height up to 1-2 meters. The root is commonly a long tap root. The nodes of ribbed stem branches bear a pair of minute scaly leaves arranged in opposite decussate manner. They join to form a two-toothed basal sheath. The stem is a photosynthetic organ and looks like a phylloclade.
Internal structure of stem
i) Epidermis:
Its outermost layer is bounded by thick epidermal cells externally protected by thick cuticles.
ii) Cortex:
The cortex is composed of usually radially elongated loosely arranged chlorenchymatous layers containing abundant chloroplasts, air cavities and inner parenchymatous cell layers.
iii) Endodermis:
The endodermal layer around the stelar region is inconspicuous.
iv) Vascular bundles:
The vascular cylinder is siphonostele type. The vascular bundles arranged in a ring are conjoint, collateral, endarch and open.
v) Medullary bundles:
The vascular bundles are separated from each other by uniseriate medullary bundles when young but become a long and broad band of lignified cells at maturity.
vi) Pith:
The central space is occupied by parenchymatous cells at the internodal region but lignified at the nodal region forming transverse plates known as peridermal diaphragms.
Sexual reproductive structure.
i) Spike like strobili:
The plant is usually dioecious and rarely monoecious. It reproduces by forming male and female small spike -like strobili borne at the axial of scale leaves.
ii) Male strobilus:
The male strobilus is a compound cone composed of a short axis bearing 2-8 pairs of opposite decussate arranged thick scales or bracts. The axil of each pair of bract except the lower one or sterile bract pairs, give off a solitary male flower or microsporangia. The staminate flower coming up from two connate perianth bears a short axis or anthophore or sporangiophore bearing two or more then or microsporangia at the tip.
iii) Female strobilus
The female strobilus or ovulate flower or Megasporangium is a compound cone. It is composed of an axis bearing common cupule formed by decussate fused 2-4 pairs of bracts or scales. The lower bract pair may remain sterile but the upper or two pairs become fertile. The fertile bract bears a single flower in its axil.
iv) Ovule
The Mature flower encloses erect ovules enveloped by outer and inner integuments. The outer integument is false formed by the extension of perianth. The inner true ovular integument prolongs out to form a thin micropylar tube characteristic of Ephedra.
