Protoplasm

Protoplasm, term once used to describe the ground substance—the living material—of cells. This material would include the complex colloidal organization of substances making up a cell's nucleus, cytoplasm, plastids, and mitochondria. The term protoplasm has to a great extent been replaced by the term cytoplasm; the latter, however, does not include the cell nucleus. Protoplasm is also used to describe the contents of the tubelike structures (hyphae) of which fungi are composed.

Ergot

Ergot, name used interchangeably for a disease of rye, for the fungus causing the disease, for the sclerotium (compact hardened mycelium, or fruiting surface) of the fungus, and for the dried sclerotium, which contains certain valuable drugs.

Ergot fungi are molds that infect rye and other cereals and wild grasses. The filamentous mycelium of the mold spreads through the tissues of the flower and attacks the ovaries, which become deformed and enlarged and then wither. The deeper mycelium within the ovary becomes dense and hard, forming sclerotium.

The dried sclerotium as used in medicine contains the crystalline alkaloids ergotamine, C33H35N5O5, and ergotinine, C35H39N5O5, and the amorphous alkaloid ergotoxine, C35H39N5O5. Histamine is also present in minute quantities. In moderate doses ergotamine causes the contraction of unstriped muscle fibers, such as those in terminal arterioles. It is used to control hemorrhage and to promote contraction of the uterus during childbirth; it is used also to treat migraine headaches. In large doses the drug paralyzes the motor nerve endings of the sympathetic nervous system. Ergotism, a disease of humans and animals, is caused by excessive intake of ergot: in humans, either by the overuse of the drug or by eating breadstuffs made with infected flour, and in cattle, by the eating of ergot-infected grain and grass. Acute and chronic ergotism are characterized by mental disorientation, muscle cramps, convulsions, and dry gangrene of the extremities. One of the psychoactive drugs, LSD is chemically related to the ergot alkaloids.

Scientific classification: Ergot fungi belong to the genus Claviceps, of the family Clavicipitaceae.

Mushroom

Mushroom, technically confined to members of a family of fungi with gills, but in popular usage any of the larger fleshy or woody fungi. The application of the term mushroom to edible species only and the term toadstool to those considered poisonous or otherwise objectionable has no scientific basis. For example, two poisonous fungi may be less closely related than are a poisonous species and an edible one.

Of the thousands of species of mushrooms known throughout the world, the great majority are tough, woody, bitter, tasteless, or of such rare occurrence that they are of no interest as food. A few species produce death or serious illness when eaten. No simple rule exists for distinguishing edible and poisonous mushrooms, but the characteristics of the more common edible species can be readily learned, and collecting activities should be confined to such species. Morels, puffballs, and other species described below are not ordinarily confused with dangerous types; whenever doubt arises, the only safe procedure is to discard all suspicious mushrooms. Fresh commercially grown mushrooms can always be eaten with safety.

Heterosporous

Spike Moss, common name for a medium-size family of primitive vascular plants. The plants are mainly of tropical distribution, growing in moist, shaded habitats. A few occur in deserts, where they become dormant during the driest parts of the year; the resurrection plant is an example of such a species. The plants of the spike moss genus are similar to those of a related genus (see Club Moss), but in the spike moss a small outgrowth, called a ligule, is located on the upper surface of each leaf close to where it joins the stem.

The spike moss is heterosporous. That is, it reproduces through the production of two kinds of spores, produced in sacs called sporangia, that are borne by specialized leaves called sporophylls. Small sacs, or microsporangia, produce many small microspores, which germinate to form short-lived, nongreen microgametophytes that produce sperm (male sexual cells). Larger sacs, or megasporangia, produce a few larger megaspores each, and these form nongreen megagametophytes that produce eggs in specialized organs called archegonia. To reach an archgonium and fertilize an egg, a sperm cell must swim in a film of water. Several species of spike moss are cultivated in tropical greenhouses for their interesting foliage.

Scientific classification: Spike mosses make up the family Selaginellaceae. The only genus in the family is Selaginella. The resurrection plant is classified as Selaginella lepidophylla.

Resurrection Plant

Resurrection Plant, common name for a fernlike, perennial desert plant, of the family of spike mosses, that ranges from the southwestern United States down to El Salvador. The flowerless plant has small, scalelike leaves and grows to a height of 10 cm (4 in). It requires little water to survive, but when completely deprived of moisture it contracts into a ball and may be borne by the wind. When it settles near water, it unfolds and is renewed—hence the name. In their dried-up state, resurrection plants are sometimes sold as novelties. The plant is sometimes called the rose of Jericho, just as that plant is often called the resurrection plant.

Scientific classification: The resurrection plant belongs to the family Selaginellaceae. It is classified as Selaginella lepidophylla.

Rose of Jericho

Rose of Jericho, also resurrection plant, common name for a small herb of the mustard family, native to Syria. It is seldom more than 15 cm (6 in) high and has small white flowers. After the herb has flowered, the leaves fall off and the branches become incurved toward the center, so that the plant assumes an almost globular form. In this state it is often blown about by the wind in the desert. When it happens to be blown into water the branches expand again, and the pods open and spill out the seeds.

Scientific classification: The rose of Jericho belongs to the family Brassicaceae (formerly Cruciferae). It is classified as Anastatica

Club Moss

Club Moss, common name for a group of plants closely related to the ferns. Two important genera are low, sometimes creeping evergreen plants that are widely distributed throughout the United States and other temperate and tropical climates. Various tropical species grow on the trunks of trees or on the ground. Usually less than 30 cm (less than 12 in) tall, the plants resemble pine in that their leaves are needlelike. Their widespread use in Christmas wreaths has brought some species close to extinction. In reproduction, spores and asexual cells borne in an elongated cone are scattered on the ground and ripen underground into sexual reproductive organs from which new plants grow.

The common club moss, also called running pine and stag's horn moss, grows in open, dry woods and rocky places. Ground pine or ground cedar has branchlets that resemble the branches of juniper. Tree moss, fir club moss, or foxfeet grows on rocks and in bogs. Fossil species, many of gigantic size, have been found in strata of the Upper Silurian and the Devonian and Carboniferous periods.

Scientific classification: The two important genera of club mosses are Lycopodium, of the family Lycopodiaceae, and Selaginella, of the family Selaginellaceae. The common club moss is classified as Lycopodium clavatum, ground pine or ground cedar as Lycopodium complanatum, and tree moss as Lycopodium selago.