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

X. SEED PLANTS

Family Fabaceae (Leguminosae)

There are 650 genera encompassing 18,000 species distributed worldwide. Among them are many valuable grain legumes, forage, medicinal, technical, and spice plants, as well as poisonous and numerous ornamental species. The family is divided into three closely related subfamilies: Caesalpinioideae, Mimosoideae, and Faboideae. On the roots of most legumes (about 70%), some mimosoids (10–15%), and certain caesalpinioids, nodule Bacteria of the genus Rhizobium establish themselves. As a result of their activity, upon penetrating the primary cortex, it proliferates to form nodules on the ROOT surface. Cyanobacteria occasionally inhabit these nodules. Through this Symbiosis with bacteria, legumes assimilate no less than 100–140 kg/ha of atmospheric nitrogen and enrich the soil with nitrogen compounds, which noticeably increases the protein content in the seeds and green mass of legumes. For this very reason, legumes are utilized as green manure. Legume seeds are exceptionally rich in protein while also containing sufficient amounts of starch. Some cultivated species accumulate high levels of fatty oils in their seeds.

Subfamily Faboideae. Herbs, shrubs, and less commonly trees, with pinnate, trifoliate, palmate, or occasionally simple leaves. Flowers are zygomorphic and pentamerous; sepals are connate and unequal; the corolla is papilionaceous, featuring an upper (largest) petal called the standard (or banner), two lateral petals called wings, and two lower connate petals forming the keel. There are ten stamens, whose filaments are usually fused into a tube (monadelphous androecium), or nine are fused with one free (diadelphous androecium); nectaries are present at their base. The pistil is single, formed from a single carpel with a superior Ovary; the fruit is a legume (pod) that dehisces along two Valves, or less frequently breaks apart into separate single-seeded segments. In the flora of Ukraine, the subfamily is represented by 53 genera and 334 species.

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Fig. 140. Marsh pea (Lathyrus palustris)

Marsh pea (Lathyrus palustris L.). A perennial herbaceous plant, 30–100 cm tall; uliginophyte, entomophilous, barochore (Fig. 140). The stem is clambering, winged, and branched. Leaves are paripinnately compound with two to four pairs of leaflets; the rachis terminates in a branched tendril. Leaflets are oblong-lanceolate, acute at the apex, entire-margined, 3–4 cm long, and up to 5 mm wide. Stipules are semisagittate, acuminate at the apex, 5–10 mm long, and 1.5–2 mm wide.

The inflorescence is a few-flowered raceme comprising three to five lilac flowers. The perianth is double and zygomorphic, 16–18 mm long. Floral formula: ↑K₅C_1+2+(2)A₁₀G₁. The fruit is a legume, 3–4 cm long, linear-lanceolate, turning nearly black upon ripening. It blooms in July–August and propagates by seeds.

The plant serves as a host for cyst-forming nematodes.

It grows in wet and waterlogged meadows, marshes, and shrub thickets within the Forest zone and Forest-Steppe.