Reproduction

The sporophyte is the conspicuous phase of the life cycle in all the plants discussed in this chapter (Fig. 21.17). A fern sporophyte consists of the fronds, a stem in the form of a rhizome, and adventitious roots that arise along the rhizome. The fronds, regardless of their ultimate form, usually first appear tightly coiled at their tips. These croziers (unrelated to the croziers of sac fungi), or "fiddle-heads" (Fig. 21.18), then unroll and expand, revealing the blades. At maturity, the blades are often divided into segments called pinnae (singular: pinna) that are attached to a midrib, or rachis. A stalk, or petiole, is usually present at the base.

When the fronds have expanded, small, often circular, rust-colored patches of powdery-looking material may appear on the lower surfaces of some or all of the blades. Because these patches appear similar to fungal rusts, some fern owners have thought their plants were diseased and have turned to sprays to deal with the "problem" or have even carefully scraped the patches off. The development of the patches is normal and healthy, however, and examination with a hand lens or dissecting microscope will reveal

The Seedless Vascular Plants: Ferns and Their Relatives

The Seedless Vascular Plants: Ferns and Their Relatives

Structure Seedless Vascular PlantsPopular Vascular Seedless Houseplants

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Essentials of Human Physiology

Essentials of Human Physiology

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