A Saprophytic Species of Catenaria Isolated from Roots of Panicum Variegatum

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Abstract
Catenaria sp. was isolated from sterilized roots of Panicum variegatum which had been placed in a battery jar containing Eriocaulon septangulare, and appears to be a saprophyte capable of growing on a wide variety of dead tissue. It has been grown successfully in plant and animal tissues including nematodes, insects, algae, mosses, ferns, and angiosperms. The thallus may be mono- or polycentric in organization, structure and development. Unicellular, spherical, oval and cylindrical thalli without any trace of rhizoids or vegetative parts as in the Myxochytridineae are not uncommon, and at maturity are transformed wholly into reproductive cells. Monocentric thalli with one to several rhizoids as in the Rhizidiaceae are frequently produced. The predominant type of thallus, however, is polycentric with numerous zoösporangia, rhizoids, and enlargements scattered irregularly along its length. In insect eggs the thallus is usually condensed and crowded, but in soft meristematic plant tissues and the internodal cells of Chara and Nitella may become distinctly mycelium-like and extend to a length of 3.2 mm. The thallus is unicellular and continuous when young, but at maturity becomes multicellular by the formation of numerous cross walls along its length. The rhizoids are likewise separated from the remainder of the thallus by septa at maturity. The zoösporangia are extremely variable in size and shape, ranging from spherical, oblong, cylindrical, amoeboid, irregular to star-shaped. Occasional enlargements occur in the thallus which may or may not develop into zoösporangia and resemble somewhat the “sammelzellen” of Physoderma and Cladochytrium. Whether or not they are to be regarded as such and occasionally serve as centers of replication is uncertain. Zoöspores are produced in great abundance and vary considerably in size. They are predominantly uniciliated, but numerous biciliated and occasional triciliated ones occur. Two cases of fusions between zoöspores or gametes have been observed.