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

VIII. BASICS OF PLANT MORPHOLOGY AND ANATOMY

Morphology and Anatomy of the Stem and Shoot

Stem Diversity

Stems exhibit A wide variety of properties.

Based on their spatial orientation (Fig. 63). Most woody and herbaceous plants have upright stems that do not require support (timothy grass, wheat, ash, oats). Stems that creep along the ground in their lower part, rise in the middle, and remain upright at the apex are called ascending. Stems that twine around other plants for support are classified as twining stems (bindweed, hops, beans) or lianas, reaching lengths of 20–300 m in the tropics. Their characteristic features include elongated vessels, a lightweight stem, uneven distribution of mechanical, vascular, and fundamental Tissues, and high light requirements. Stems equipped with tendrils and holdfasts that allow the plant to climb tree trunks, rocks, or walls form a group of climbers (wild grapes, ivy). Some plants have prostrate stems that spread along the ground (Fig. 63). Depending on the length of the shoots and internodes, they are practically divided into runners and stolons (strawberries). Plants use the latter for propagation. A stem that grows horizontally, lies on the soil surface, and does not ROOT is called a decumbent stem (watermelon, melon).

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Fig. 63. Types of stems:

1 - erect, 2 - ascending, 3 - clambering, 4 - twining, 5 - creeping

A horizontally growing or prostrate stem that roots at the nodes is called a creeping stem (ground ivy, creeping buttercup).

A leafless stem that bears a single inflorescence or flower is called a scape (onion, garlic). The leaves form a rosette at ground level.