Symbiotic Forms Research Articles

Growth of Chondromyces crocatus in pure culture.

THE genus Chondromyces was named and illustrated, but not described, by Berkeley and Curtis in 1857 in Berkeley's1 “Introduction to Cryptogamic Botany”. It was apparently next seen by Thaxter2, who reported that he grew it in pure culture. In 1913, this species was stated by Pinoy3 to grow only in the presence of Micrococcus. Beebe4 reported the presence of C. crocatus; but attempts to purify the organism failed completely though it grew readily with various bacteria in mixed culture. Kuhlwein5 stated that C. crocatus could not be grown in pure culture and that it was a symbiotic form. Oetker6, recently, has shown that several species in the genera Myxococcus and Podangium can grow upon yeast and algae.

Ferns and Fungi

It will perhaps come as a surprise to fern lovers to learn that these interesting and often delicate plants are as much subject to attack by parasitic fungi as are the higher plants. The fungi occur not only as parasites, but as symbiotic forms in the roots, as epiphytes on fronds and stems, and in a wide and bewildering variety as saprophytes or scavengers on all parts of dead and dying plants. Even the prothallia of ferns are attacked and destroyed by a number of the lower fungi. Seymour in his standard Host of the Fungi of North America lists approximately 200 species of fungi as growing on nearly 100 fern species-an array of enemies to make the stoutest fern quail! Pteridium, the common Bracken, for example, is host to some 30 fungi, a number of them distinctly parasitic. A forthcoming supplement to the Index will increase this record substantially. The interrelationship, as alternate rust hosts, which exists between the wheat crop and the barberry and between our white pines and currant bushes to their mutual disadvantage has been thoroughly publicized. It is not so well known, though unfortunately only too true, that a considerable number of North American ferns and our fir forests are involved in a similar rust fungus complex. There are three such rust genera, concerned, all abundantly represented in this country: Uredinopsis, Milesia,

Biological and toxicological studies upon Penicillium puberulum Bainier

This species when grown upon Raulin's solution, in pure culture, produces a new organic acid which has been termed penicillic acid. This acid gives a brownish-red solution when treated with a dilute solution of ferric-chloride. With ammonia it gives a deep red color. From the analyses, molecular weight determinations and other data, it seems probable that this acid belongs to the same general class of compounds as are found in lichens, and termed lichen acids. Like them, it is slightly bitter and irritating. Pharmacologically, it is moderately toxic, having an antiseptic action and being a protoplasmic poison. It is not astonishing to find substances of this class in fungi, since lichens are symbiotic forms, composed of fungi and algae. The finding of this type of substances in the pure culture of a fungus makes it probable that in lichens, lichen acids are the product of the fungus metabolism, and not of that of the algae.