Part 6

4. PERICHÆNA MARGINATA, Schw. Sporangia depressed, polygonal, approximate and sometimes confluent, the surface cinereous-pulverulent, seated on a silvery hypothallus; the wall firm, thick, the outer surface yellow-brown, covered with minute whitish scales, the inner surface yellow, deeply reticulately impressed by the spores which rest against it, dehiscent in a circumscissile manner. Capillitium consisting of a few simple or somewhat branched threads or well-nigh obsolete. Spores subglobose, yellow, 12-14 mic. in diameter.

Growing on the outer surface of the bark of Acer, Fagus, etc. Sporangia .4-.6 mm. in width. This is plainly Perichæna cano-flavescens, Raunkier. I do not find any threads of a capillitium in my specimens.

II. OPHIOTHECA, Currey. Plasmodiocarp terete and more or less elongated, bent and flexuous, sometimes annular or reticulate, the surface not polished or shining: the wall a thin membrane, with a thin outer layer of minute scales and granules, irregularly dehiscent. Capillitium of very slender loosely-branched threads, with the surface minutely warted and spinulose. Spores globose, oval or somewhat irregular, yellow.

Distinguished from Perichæna by the terete plasmodiocarp and by the more spinulose capillitium. Cornuvia of Rostafinski.

1. OPHIOTHECA CHRYSOSPERMA, Currey. Plasmodiocarp globose or oblong to elongated, and bent or flexuous, sometimes annular or branched and reticulate, dull brown in color; the wall a thin yellowish membrane, with a thin yellow-brown outer layer, irregularly dehiscent. Capillitium of slender loosely-branched threads, 2-3 mic. in thickness, the surface minutely spinulose. Spores subglobose, yellow, 8-9 mic. in diameter.

Growing on the inner surface of old bark of Quercus, etc. Plasmodiocarp .4-.5 mm. in thickness, variable in length. Cornuvia circumscissa of Rostafinski's monograph.

2. OPHIOTHECA WRIGHTII, B. & C. Plasmodiocarp more or less elongated, bent and flexuous, very commonly in small rings, from brownish-ochre to brown or blackish in color, not polished; the wall a thin yellow membrane, with a thin brown outer layer, irregularly dehiscent. Capillitium of slender loosely-branched threads, 2-3 mic. in thickness, furnished with numerous straight or bent long-pointed spinules. Spores subglobose, yellow, minutely warted, 10-12 mic. in diameter. See Plate I, Fig. 14.

Growing on the inside of bark of Acer, Carya, etc. Plasmodiocarp about .5 mm. in thickness, variable in length, often in small rings 1-2 mm. in diameter. The prickly threads are quite characteristic; the spinules are 3-5 mic. in length. Hemiarcyria melanopeziza, Speg., is evidently the same thing.

3. OPHIOTHECA VERMICULARIS, Schw. Plasmodiocarp terete and more or less elongated, bent and flexuous, sometimes annular or reticulate, the surface not polished, brownish in color; the wall a thin yellow membrane, covered on the outside by a more or less thickened brown layer of scales and granules, irregularly dehiscent. Capillitium of slender loosely branched threads, 2-3 mic. in thickness, the surface with minute warts and ridges. Spores subglobose, yellow, 10-12 mic. in diameter.

Growing on the inside of old bark. Plasmodiocarp about .4 mm. in thickness and various in length; in my specimens the sporangia are mostly small rings. The species looks exactly like Ophiotheca Wrightii, but the character of the threads is quite different.

4. OPHIOTHECA PALLIDA, B. & C. Plasmodiocarp terete, oblong or elongated annular and flexuous, the surface dull, pale ochraceous; the wall a thin pellucid membrane, minutely granulate, with a thin pale ochraceous outer layer, irregularly dehiscent. Capillitium of slender loosely-branched threads, 2-3 mic. in thickness, the surface minutely warted or spinulose. Spores subglobose, pale yellow, 10-12 mic. in diameter.

Growing on dead stems of herbaceous plants. Plasmodiocarp .3-.4 mm. in thickness, variable in length, sometimes short and roundish or oblong, sometimes much elongated and flexuous. More delicate than Ophiotheca vermicularis, and distinguished by its pallid color throughout.

ORDER IV. ARCYRIACEÆ.

Sporangia regular and stipitate, rarely sessile; the wall a thin membrane, minutely granulose, colored as the spores and capillitium, the upper part soon torn away in a somewhat circumscissile manner, and early disappearing. Capillitium of slender tubules, repeatedly branching and anastomosing to form a complicated network of evident meshes, more or less expanded after dehiscence; the surface of the threads minutely warted or spinulose or with elevated ridges in the shape of rings, half rings or reticulations.

This order is specially distinguished by the threads of the capillitium forming a complicated network of evident meshes.

TABLE OF GENERA OF ARCYRIACEÆ.

1. LACHNOBOLUS. Capillitium of slender tubules, quite variable in thickness, proceeding from numerous points of the sporangial wall.

2. ARCYRIA. Capillitium of slender tubules, issuing from the interior of the stipe, the network without any free extremities.

3. HETEROTRICHIA. Capillitium issuing from the interior of the stipe, the peripheral portion of the network bearing numerous short acute free branches.

I. LACHNOBOLUS, Fr. Sporangia stipitate or sessile, the wall a thin delicate membrane, minutely granulose, rupturing irregularly. Stipe short or sometimes wanting. Capillitium of slender tubules quite variable in thickness, proceeding from numerous points of the sporangial wall and forming a complicated network, the surface minutely warted or spinulose. Spores globose, yellowish or flesh-color.

This genus differs from Arcyria in the capillitium springing from numerous points of the sporangial wall.

1. LACHNOBOLUS GLOBOSUS, Schw. Sporangia globose, stipitate, pale yellow, changing to clay-color; the wall thin and delicate, pellucid, minutely granulose, the upper part torn away and soon disappearing, the lower half more persistent. Stipe short, tapering upward, expanding at the base into a small hypothallus. Capillitium arising from the lower portion of the sporangium, forming a complicated network, the threads 3-5 mic. in thickness, the surface closely covered with minute warts. Spores globose, pale yellow to clay-color in mass, 8-9 mic. in diameter. See Plate I, Fig. 15.

Growing on the spines of Chestnut burs. Sporangia .5-.6 mm. in diameter, the stipe shorter than the sporangium.

2. LACHNOBOLUS INCARNATUS, A. & S. Sporangia globose or ellipsoidal, substipitate, closely crowded and seated on a common hypothallus; the wall thin and delicate, pellucid, minutely granulose, dehiscing irregularly. Stipe very short or often obsolete. Capillitium proceeding from the inner surface of the sporangial wall, forming a complicated network, the threads extremely variable in thickness, minutely warted and spinulose. Spores globose, flesh-color in the mass, 8-9 mic. in diameter.

Growing on old wood. Sporangia .5-.8 mm. in height, sessile on a narrow base or with a very short stipe; the threads of the capillitium are generally 3-5 mic. in thickness, but there are broader expansions at the nodes and elsewhere. My specimens are from Prof. McBride, of Iowa. The species is extremely variable, and these specimens differ much from those described elsewhere.

II. ARCYRIA, Hill. Sporangia regular ovoid to cylindric, stipitate; the wall a thin delicate membrane, circumscissile or torn away near the base, the upper portion evanescent, the lower part persistent, small and cup-shaped. Stipe more or less elongated, the interior containing roundish vesicles which become smaller upward, and gradually pass into the normal spores. Capillitium of slender tubules, issuing from the interior of the stipe, forming a complicated network, without any free extremities, the surface minutely warted or spinulose or with annular ridges. Spores globose, red, brown, yellow, cinereous.

§1. CLATHROIDES, Mich. Capillitium closely attached by a few threads which issue from the interior of the stipe, and are free from the calyculus (except in A. punicea), much elongated after dehiscence, weak and drooping or prostrate; the meshes open and irregular, not differing externally and internally, their threads similar throughout, the warts or ridges of the surface exhibiting a spiral arrangement.

1. ARCYRIA PUNICEA, Pers. Sporangium ovoid, more or less elongated; the calyculus small, plicate-sulcate. Stipe long, erect, brownish-red in color, expanded at the base into a small hypothallus. Capillitium firmly attached by numerous threads which are connate with the wall of the calyculus, much elongated after dehiscence, ovoid-oblong to cylindric, bright red in color, fading to red-brown or brownish-ochre; the threads uniform in thickness, about 3 mic., the surface with a series of prominent half-rings, which wind around the thread in a long spiral. Spores globose, even, 6-8 mic. in diameter.