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

X. SEED PLANTS

Family Ruppiaceae.

Comprises six to eight species distributed in saline and, more rarely, fresh Water bodies. It is close to the previous family, but differs in that the flowers lack a perianth. There are two stamens, and sessile pistils consisting of 4 (10) carpels. Flower formula: * P₀ A₂ G₄₍₁₀). Fruits are drupe-like. There are three species in Ukraine.

Beaked tasselweed (Ruppia maritima L.). A perennial plant with submerged thread-like stems and thread-like leaves that have expanded sheaths at the base. Flowers are bisexual, pedicels are 1-3(6) cm long, bearing two closely spaced flowers (Fig. 183). Perianth appears as two triangular membranous scales. Two stamens, apocarpous gynoecium consisting of 2(10) carpels. Blooms in June–September. Fruit is an aggregate drupe, fruitlets up to 2.4 mm long, with a relatively long beak.

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Fig. 183. Beaked tasselweed (Ruppia maritima)

Grows in coastal lagoons, saline lakes, at a depth of 100-150 cm; when water bodies dry up, it vegetates as an annual.

Distributed in the southern part of the Steppe zone, the Dnieper Estuary, and the shallow waters of the Black Sea coast. In North America, it is cultivated as a forage plant for waterfowl. A technical, forage, phytomeliorative, and water-protection plant. Other species: spiral ditchgrass (R. spiralis L.), distinguished by its fruitlets twisted into a spiral, and curved tasselweed (R. cirrhosa (Petanga) Grande), featuring long curved pedicels.