BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

X. SEED PLANTS

Family Najadaceae (Naiads).

Includes 2 genera with 40–50 species distributed worldwide. Annual plants with forked stems; leaves opposite, with expanded sheathing bases and sinuate-toothed margins. Flowers solitary, apetalous, unisexual. Formula of the male flower: P₀ A₁, of the pistillate flower: P₀ G(_2-3). Fruit single-seeded, drupe-like. Ukraine is home to 2 genera and 3 species.

Naiad (Najas marina L.). A dioecious plant with a branched, brittle stem 10-60(100) cm long. Leaves linear, wavy-margined, sinuate-toothed. The blade is 1^1 mm long, arranged in semi-rings, with broad-lobed stipules. Stems and leaves bear spines along the midrib. Flowers unisexual, located in the axils of leaf sheaths near branch bases; blooms from June to September. Fruit - a single-seeded samara. A highly polymorphic species. Grows in brackish lakes, coastal lagoons, oxbow lakes, and basins of major rivers, such as the Southern Bug, Dnieper, and Danube.

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Fig. 184. Najas marina

The vegetative biomass contains Proteins (up to 18.5%), fats (up to 2%), fiber (up to 33%), carotene (3 mg per kg), CARBOHYDRATES (up to 26%), as well as micro- and macroelements.

A forage and fishery plant consumed by rudd, river flounder, and carp. Water-protective - potentially useful for wastewater Treatment.

Another species of the genus, Najas major All. (= N. marina var. grandifolia), differs from the previous species by larger leaves (up to 6.6 mm) with a barely noticeable tooth along the margin. It occurs in freshwater bodies throughout Ukraine and serves as an indicator of water pollution and anthropization.

Brittle water-nymph (Caulinia minor (All.) Coss. et Germ.). An annual with submerged stems and leaves. Leaves linear, sheathing, with a toothed margin, the midrib lacking spines. Flowers solitary, unisexual. Staminate flowers with a single stamen and a bilobed perianth, often spatheate. Pistillate flowers naked, with or without a spathe. Blooms underwater from June to September. A hydrophilous plant. Fruit - a narrow-elliptic capsule. Seeds covered with a wrinkled seed coat.

Grows in standing and slow-flowing water bodies, widespread throughout Ukraine, primarily in the Forest-Steppe and Steppe zones. In Lviv Oblast, it is included in the Regional Red List of protected plants.