30 



found only on chestnut burs, and brown like C. minutum but 

 with yellow or brown lime-knots. 



Genus 5. LEOCARPUS 



There is but one species, L. fragilis, which is very common 

 and easily recognized. The sporangia are large, up to 4 mm. in 

 total height, obovoid or somewhat lengthened, and of a yel- 

 lowish to chestnut or purple-brown color. The peridium or 

 sporangium-wall is smooth, shining, tough and brittle, often 

 contracted or shrunken as it surrounds loosely the enclosed 

 capillitium and spores. The lime-knots are large and brown but 

 often faded to white; and together with the spores present a 

 dark appearance, under a hand lens, when the wall has ruptured. 

 The stalks are membranous, yellowish, and weak, so that the 

 sporangia are often recumbent, and arise from a spreading base 

 of the same color, which is called a hypothallus. 



Genus 6. DIDERMA 



We now come to a genus in which granular lime will be pres- 

 ent in the peridium, stalk, or columella, or all of them together, 

 but not in the capillitium like in Badhamia, Physarum and allied 

 genera. The capillitium consists of hyaline, purplish, or dark 

 purplish threads without lime. The common species, found 

 everywhere on leaves in damp places, is D. effusum. It forms 

 white, sessile, flattened sporangia and plasmodiocarps, usually 

 irregular in shape, and the plasmodiocarps often effused like a 

 thin smear. The columella is depressed, in many instances 

 hardly more than a yellowish or reddish-brown inside base. 

 D. testaceum, also common on leaves, forms similar depressed 

 sporangia, but they are more circular, and pinkish when fresh, 

 although rapidly fading to white. The columella there is large, 

 convex or hemispherical, and reddish-brown. D. floriforme is a 

 stalked form found on very rotten wood. The yellowish stalk is 

 rather stout and long supporting a globose, yellowish sporan- 

 gium with a tough wall, which, when it opens, splits in a petal- 

 like manner and exposes the almost black, spherical mass of 

 capillitium and spores. Within the capillitium is a large, globose, 

 yellowish columella coming from the stalk. The form, when open 

 and expanded, looks like a miniature flower. The spores have 

 large scattered warts which distinguishes it from D. radiatum 



