Figure 478.—Catastoma circumscissum.
Circumscissum means divided into halves.
The peridium is usually round, more or less depressed, commonly rough because of the soil attached; the larger part of the plant remaining in the soil as a cup; the upper part with the inner peridium, depressed-globose, thin, pallid, becoming gray, with branny scales, with a small basal mouth. A thin spongy layer will frequently be seen between the outer and inner peridium. The mass of the spores is olivaceous, changing to pale-brown. The spores are round, minutely warted, 4–5µ. in diameter, often with very short pedicels.
The plants are usually found in pastures along paths. I have seen them in several parts of Ohio. They are found from Maine to the western mountains. This is called Bovista circumscissa by Berkeley.
There is a species of a western range called C. subterraneum. This differs mainly in having larger spores. It seems to be confined to the middle west. However, it does not grow under the ground, as its name would suggest.
There is also another species called C. pedicellatum. This species seems to be confined to the southern states and differs mainly in the spores having marked pedicels and closely warted.
Podaxineæ.
This tribe is characterized by having a stalk continuous with the apex of the peridium, forming an axis. Some of the plants are short stalked, some long stalked. The tribe forms a natural connecting link between the Gastromycetes and the Agarics. Thus: Podaxon is a true Gastromycetes, with capillitia mixed with spores; Caulogossum, with its permanent gleba chambers, is close to the Hymenogasters; Secotium is only a step from Caulogossum, the tramal plates being more sinuate-lamellate; and Montagnites, which is usually placed with the Agarics, is only a Gyrophragmium with the plates truly lamellate.
| Gleba with irregular, persistent chambers— | ||
| Peridium, elongated club-shaped | Cauloglossum. | |
| Peridium, round or conical, and dehiscing by breaking away at the base | Secotium. | |
| Gleba with sinuate-lamellate plates | Gyrophragmium. | |
| Walls of gleba chambers not persistent | Podaxon. | |