This genus has but three known American species. The plants are remarkable in structure and substance. The spore mass or gleba lies at the centre of a base, and is in its young stages surrounded by four layers. The outermost coat is gelatinous, and soon disappears. This is known as the volva or wrapper. The layer just within the wrapper also soon disappears ; it is known as the exoperidium. The layer just within the exoperidium is known as the endoperidium, and is the layer seen on the exterior of older specimens. Between the exope-ridium and endoperidium is a layer of red threads, part of which is torn away when the exoperidium breaks, and a part of which remains as a red star at the apex of the ball.
The exoperidium is cartilaginous ; it is thin and fragile when dry, but when wet it is flexible, translucent, and soft. The endoperidium is hard and rigid when dry, and is conspicuous for the brilliant red which shows at its mouth. Within the endoperidium is a sac which contains the spores ; when the spores are mature, this sac contracts, and forces the spores out into the air. The mycelium, or vegetative part of the Calostoma plant, is composed of numerous cord-like fibres, translucent, jelly-like, and tough, which, branching and anastomosing into a dense network, form a rooting columnar base to the spore-bearing part of the plant. The name Calostoma means beautiful mouth, referring to the red star which surrounds the opening through which the spores escape.
Ball or Peridium - Globular, with a thick, entangled, rooting base.
Outer Coat or Exoperidium - Dingy yellow, rupturing so as to form a ragged collar at the base, a thin cap on the summit, and small fragments between. The cap is marked on the under side with a vermilion star outlined with yellow.
Inner Coat or Endoperidium - Smooth, globular. Pale yellow.
Mouth - With several rays of a bright red colour.
Footstalk - Thick, of entangled strands finer than those of C. cin-nabarinum. Stem long, yellowish green.
Spores - Globular, with protuberances.
Ball or Peridium - Globular, with a thick, entangled, rooting base. Outer Coat or Exoperidium - Cartilaginous, gelatinous. Fragments remain upon the inner coat in the form of irregular warts or scales. Inner Coat or Endoperidium - Yellowish. Tough when wet, rigid when dry. Mouth - Red starred. Footstalk - Short and rooting, composed of mycelial threads netted to form cartilaginous cords. Spores - Elliptical, oblong, smooth.
Outer Coat or Exoperidium - Vermilion within, breaking at the base and sometimes at the apex. Inner Coat or Endoperidium - Yellowish, often slightly vermilion.
Smooth. Mouth - Rays several. Vermilion. Footstalk - Reddish brown or brownish. Spores - Elliptical oblong, spined or punctured, pale ochre yellow.
Lu-tes'-cens Ra'-ven-el'-I-I Cin'-na-ba-ri'-num