Related to the puff-balls, and properly classed with them, are the species of Scleroderma. This name is given to the genus because of the hard peridium, the wall being much firmer and harder than in Lycoperdon. There are two species which are not uncommon, Scleroderma vulgare and S. verrucosum. They grow on the ground or on very rotten wood, and are sessile, often showing the root-like white strands attached to their base. They vary in size from 2–6 cm. and the outer wall is cracked into numerous coarse areas, or warts, giving the plant a verrucose appearance, from which one of the species gets its specific name.
Calostoma cinnabarinum Desv.—This is a remarkably beautiful plant with a general distribution in the Eastern United States. It has often been referred to in this country under the genus name Mitremyces, and sometimes has been confused with a rarer and different species, Calostoma lutescens (Schw.) Burnap. It grows in damp woods, usually along the banks of streams and along mountain roads. It is remarkable for the brilliant vermilion color of the inner surface of the outer layer of the wall (exoperidium), which is exposed by splitting into radial strips that curl and twist themselves off, and by the vermilion color of the edges of the teeth at the apex of the inner wall (endoperidium). The plant is 2–8 cm. high, and 1–2 cm. in diameter. When mature the base or stem, which is formed of reticulated and anastomosing cords, elongates and lifts the rounded or oval fruiting portion to some distance above the surface of the ground, when the gelatinous volva ruptures and falls to the ground or partly clings to the stem, exposing the peridium, the outer portion of which then splits in the manner described.
When the plant is first seen above the ground it appears as a globose or rounded body, and in wet weather has a very thick gelatinous layer surrounding it. This is the volva and is formed by the gelatinization of the outer layer of threads which compose it. This gelatinous layer is thick and also viscid, and when the plants are placed on paper to dry, it glues them firmly to the sheet. When the outer layer of the peridium splits, it does so by splitting from the base toward the apex, or from the apex toward the base. Of the large number of specimens which I have seen at Blowing Rock, N. C., the split more often begins at the apex, or at least, when the slit is complete, the strips usually stand out loosely in a radiate manner, the tips being free. At this stage the plant is a very beautiful object with the crown of vermilion strips radiating outward from the base of the fruit body at the top of the stem, and the inner peridium resting in the center and terminated by the four to seven teeth with vermilion edges. At this time also the light yellow spore mass is oozing out from between the teeth. The spores are oblong to elliptical, marked with very fine points, and measure 15–18 × 8–10 µ.
Plate 82, Figure 211.—Calostoma cinnabarinum. See text for colors (natural size).
Figure [211] is from plants collected at Blowing Rock, N. C., in September, 1899. The Mytremyces lutescens reported in my list of "Some Fungi of Blowing Rock, N. C.," in Jour. Elisha Mitchell Sci. Soc. 9: 95–107, 1892, is this Calostoma cinnabarinum.
CHAPTER XV.
THE STINK-HORN FUNGI: PHALLOIDEAE Fries.
Most of the stink-horn fungi are characterized by a very offensive odor. Some of them at maturity are in shape not unlike that of a horn, and the vulgar name is applied because of this form and the odor. The plants grow in the ground, or in decaying organic matter lying on the ground. The spawn or mycelium is in the form of rope-like strands which are usually much branched and matted together. From these cords the fruit form arises. During its period of growth and up to the maturity of the spores, the fruit body is oval, that is, egg form, and because of this form and the quite large size of these bodies they are often called "eggs." The outer portion of the egg forms the volva. It is always thick, and has an outer thin coat or membrane, and an inner membrane, while between the two is a thick layer of gelatinous substance, so that the wall of the volva is often 3–6 mm. in thickness, and is very soft. The outline of the volva can be seen in Fig. [215], which shows sections of three eggs in different stages. Inside of the volva is the short stem (receptacle) which is in the middle portion, and covering the upper portion and sides of this short stem is the pileus; the fruit-bearing portion, which is divided into small chambers, lies on the outside of the pileus. In the figure there can be seen cross lines extending through this part from the pileus to the wall of the volva. These represent ridges or crests which anastomose over the pileus, forming reticulations. The stem or receptacle is hollow through the center, and this hollow opens out at the end so that there is a rounded perforation through the upper portion of the pileus.