The Mycorhiza of Tipularia unifolia* 



Ey Julia B. Ci.iitom) 



(Plate 372) 



The writer of this paper undertook a study of the anatomical 

 and physiological relations of Tipularia and its symbiotic fungus, 

 for the purpose of extending information on mycorhizal adapta- 

 tions, and thus affording a wider basis for the determination of the 

 actual relation between plants associated in this manner. 



The material examined consisted of a number of living speci- 

 mens from South Corolina, which were grown in the greenhouse 

 of the University of Minnesota. The plant consists of an irregu- 

 lar solid corm w^hich sends out an offset in midsummer, from wdilch 

 is formed a daughter corm, giving rise to a single ovate leaf in the 



autumn which survives the winter. In the spring the leaf dies 

 away and the corm sends up a scape 49 to 50 centimeters high, 

 bearing a raceme of greenlbh flowers. Tlie roots are ^cw in num- 

 ber, fibrous, and depend from the base of the corm. 



Structure of the Roots 



TJic Stele. — The stele is tetrarch, well developed, and fairly large 

 for the size of the root, each bundle consists chiefly of two or three 

 large scalariform ducts and a number of spiral vessels. Alternat- 

 ing with the bundles are groups of twelve to twenty sclerenchy- 

 matous fibers in which the lumen is almost obliterated. The 

 pericycle is interrupted, and its elements are quite irregular in ma- 

 ture organs. The endodermal cells are large, uneven in size, the 

 lateral walls are sometimes thickened, and all are suberized. 



The Cortex. — External to the stele is a region of the cortex 

 consisting of four to six layers of short cylindrical cells, with 

 small intercellular spaces, and thin cellulose walls. These cells 

 contain large fungal vesicles in contact with the nuclei and those 



of neighboring elements may be seen to be connected by hyphal 



* The ^vork described in this paper was done in the physiological laboratory of the 

 University of Minnesota, under the direction of Professor D. T. MacDougal of the New 

 York Botanical Gardens, who also revised the manuscript. 



( C35 ) 



