Page:The New International Encyclopædia 1st ed. v. 02.djvu/646

and for an account of the structure and habits of these groups, see Ustilaginales and Uredinales.

In this brief account, attention must be given chiefly to the mushrooms, toadstools, bracket fungi, and puffballs, which comprise the bulk of the Basidiomycetes. In these groups the spore-bearing surface (hymenium) covers specialized regions of the body, the most familiar being the knife-blade-like plates or gills of most toadstools (Acricales), the minute pores in the under side' of the bracket-fungi (Polyporales), and the pointed teeth in the hynales. In the puffballs, the spore-bearing surface lines a labyrinth of chambers ('gleba') in the interior, which become quickly disorganized so that the mature puffball is hardly more than a capsule ('peridium') inclosing a powdery mass of spores. The structures called toadstool, bracket-fungus, or puffball, are really only the fructifications of extensive thready bodies (mycelium) that penetrate the substratum in all directions. Thus the toadstools and mushrooms (edible toadstools) that come up on the lawns and in pastures have been formed and nourished by a cobweb-like growth of filaments that spreads through many square feet of the soil. Such forms often appear in more or less complete circles ('fairy rings'); which indicates that the body is advancing through the soil from some centre of infection.

The toadstool develops from a small ovoid body beneath the surface of the ground. In this structure the parts of the mature fructification are differentiated, so that the latter may quickly expand at maturity. The stalk ('stipe') then rapidly elongates, carrying aloft the cap ('pileus') and frequently leaving at the base a sort of cup ('volva') into which the stalk fits. In some forms there is also a ring just below the cap (pileus), which ring is the remnant of a membrane that held the pileus folded against the stalk. The presence or absence of a volva or ring, the structure of the gills, and the color of the spores are the most important systematic characters of toadstools. Thus, the members of Amanita, the most dangerous genus among the toadstools, has white spores, a volva, and a ring.

BASIDIOMYCETES. A common mushroom: 1. longitudinal section, showing stipe (s), pileus (p), and gills (l); 2. the pileus from beneath: s, magnified view of a section of two gills, showing how the spores are attached.

The puffballs (Gasteromycetes) present various conditions with respect to the structure of the parchment-like envelope (peridium), which may be simple, rupturing irregularly; or composed of several layers and provided with special openings for the escape of spores. The 'Earth stars' (Geaster) and the 'Bird's-nest fungi' (Nidulariales) are highly developed types.

Very different is the group of the 'Stink-horns' (Phallales ) . This order comprises a series of forms very remarkable in their structure and development, but whose habits take away any natural beauty. The masses of spores are exposed on a stalked structure that emits the most penetrating odor of carrion. It is interesting to know that this scent attracts flies, and probably serves a useful purpose to the plant in distributing the spores.

For an extensive account of the Basidiomycetes, consult Engler and Prantl, Die natürlichen Pflanzenfamilien (Berlin, 1899); and in English, Stevenson, British Hymenomycetes (London, 1886). A large number of books on toadstools and mushrooms have been published in America, the most extensive being Atkinson, Studies of American Fungi (Ithaca, 1900). See Mushroom; Fungi; and plates illustrating these articles.

Agaricus canipestris. the common edible mushroom: 1. general habit, showing mycelium (m), stipe (s), annulus (a), and pileus; 2. portion of gill highly magnified, showing the basidia (b) with their spores, and the hyphæ (d) from which they arise.

BASIL, baz'il (Gk. βασιλικός, basilikos, royal) (Ocimum). A genus of plants of the natural order Labiatæ (q.v.). The species are all natives of the tropics, or of the warmer temperate parts of the world, and are generally characterized by a pleasant aromatic smell and taste. Sweet Basil (Ocimum basilicum) is an annual plant, a native of the East Indies, about one foot high, with ovate or oblong leaves, which has long been cultivated in Europe for seasoning food. Bush Basil (Ocimum minimum) and Tree Basil (Ocimum gratissimum) , also natives of the East Indies, are cultivated in gardens for the same purpose. Ocimum campechianum is a native of Florida and tropical America. Basil is a common name for Pycnanthemum, a