Botanical Gazette Volume 18 (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: i Thus we see that work upon the roots of this order, especially as to the meristem, has been very limited. In the parts o,f this paper which follow I have endeavored to point out certain types of structure, as I have found them in the roots of the native species of Ranunciilacece. University of Chicago. Method for obtaining pure cultures of Pammel's fungus of Texas root rot of cotton.1 GEO. F. ATKINSON. It is not a very difficult matter to obtain artificial pure cultures of spore producing fungi which grow readily in artificial nutrient media. But when we meet with forms of fungi, the spore production of which is unknown, quite a serious difficulty is encountered since spores of other fungi, as well as numerous bacteria, are so apt to be securely lodged in the strands of the mycelium. This serious difficulty is increased when the fungus in question shows a decided aversion to growing on the usual artificial media. The fungus of Texas root rot of cotton, described by Pammel in Bulletin no. 7 of the Texas Agricultural Experiment Station, has not yielded to the methods usually resorted to in obtaining pure cultures. After trying various methods Pammel failed to obtain a pure culture. In one case threads of the fungus were swept with a camel's hair brush with the hope of obtaining spores. A "pure culture of some fungus" was obtained but its morphological characters were unlike those of the fungus found on the roots of cotton. During the summer of 1891, at Auburn, Ala., I made several attempts from fresh material received from Texas to induce the fungus to part its hold on the cotton roots and grow under my care and observation. All attempts at that time failed. Affected roots were placed on sand in moist chambers and the fungus strands grew in several cases fr...