Botany - B.Ye. Yakubenko 2017

Part Three. Plant Kingdom (Plantae)
Chapter IX. Division Angiosperms, or Flowering Plants (Angiospermae, Magnoliophyta)
Laboratory Class Topic 14.53. Frogbit Family (Hydrocharitaceae)

General Remarks. This family includes perennial, herbaceous plants that either float on the Water surface or remain submerged. The leaves are basal or cauline, with stipules. The flowers are solitary or arranged in umbellate inflorescences, mostly unisexual, actinomorphic, and enclosed in a spathe of two membranous bracts before opening. The plants are predominantly dioecious. The perianth consists of six segments arranged in two whorls of three, with the outer segments green and the inner ones petaloid, sometimes the perianth is formed by three segments only. Staminate flowers bear 3–15 stamens, while pistillate flowers contain a single pistil formed by 3–6 carpels. The fruit is a berry with a leathery pericarp. These plants propagate well vegetatively and produce wintering buds. They generate a substantial vegetative mass and are used as pig feed, fertilizer, grazed by aquatic fauna, and are suitable for cultivation in artificial water bodies and aquariums (such as water soldier, frogbit, elodea, and tapegrass).

Objects:

1. Water soldier (Stratiotes aloides L.)

2. European frogbit (Hydrocharis morsus-ranae L.)

2. Canadian waterweed (Elodea сanadensis C. Rich.)

3. Tapegrass (Vallisneria spiralis L.)

Tasks:

1. Perform a morphological Analysis of the plants from the Hydrocharitaceae family.

2. Examine, describe, and sketch the characteristic taxonomic features of plants belonging to the Hydrocharitaceae family.

3. Identify the available plant species. Record the identification Procedure in your notebook.

4. Write down the floral formulas and draw the floral diagrams of the identified plants.

Equipment and Materials: live, fixed, and herbarium specimens, hand lenses, dissecting needles, Microscope slides, charts, and taxonomic keys.

Macroscopic Study of the water soldier (Stratiotes aloides L.) A perennial, aquatic, floating plant featuring shortened creeping shoots and adventitious roots. The numerous, sessile, trigonous-ensiform, spinose-serrate leaves form a basal rosette and rise above the water surface. The inflorescence is an axillary umbel. The flowers are unisexual and actinomorphic, and the plants are dioecious. The perianth is double, consisting of six segments, with the inner three segments being white. Staminate flowers occur in groups of several within a two-bract spathe, possessing 10–15 developed stamens and numerous filiform staminodes; pistillate flowers occur singly or in pairs, with 6 stigmas. The fruit is a berry. Floral formula: *Ca₃Co₃A_10—15G₀; *Ca₃Co₃A₀G₍₆₎.

Other species are studied and identified following the same procedure.

Conclusion. Hydrocharitaceae are aquatic, perennial herbaceous plants that float or are submerged in water. Their flowers are unisexual, and the plants are dioecious. They possess a high capacity for Vegetative Reproduction, which can lead to the overgrowth of water bodies.

Class="center">Self-Assessment Questions

1. What life forms are represented within the Hydrocharitaceae family?

2. To which ecological group do the Hydrocharitaceae belong?

3. Based on what characteristics are Hydrocharitaceae classified as monocotyledons?

4. Do Hydrocharitaceae possess roots?

5. What type of flowers is characteristic of Hydrocharitaceae?

6. Name the ornamental species of Hydrocharitaceae.

7. Which plant from the Hydrocharitaceae family is commonly known as "water plague"?