1922] Essig: Morphology of Schizophyllum commune Fries 459 



(California Bay) in the field near the laboratory where more than 

 a hundred sporophores have grown during the autumn and winter of 

 1919-1920; and in the laboratory where scores of sporophores have 

 appeared upon the wood of Aoacia, Quercus, and Umbellulwria in moist 

 chambers. Dozens of the fruit bodies have been sectioned, either longi- 

 tudinally or transversely. 



No phenomena in the course of the development of the sporophores 

 have been observed that in any way approximated those described by 

 Adams (1918) for Schizophyllum commune. By cutting oblique sec- 

 tions through small mature specimens his figures 2 to 7 in plate 9 

 may be imitated with fair accuracy, but these sections cannot permit 

 of such an interpretation as he has given for his sections. The crena- 

 tures which he shows in figures 2 to 5, plate 9, are entirely absent in 

 all of the 160 or more young specimens the writer has examined. The 

 sporophores which grew here in the laboratory and in the field devel- 

 oped much as was described by Hasselbring (1907). 



The fruit bodies appear first as small, loose tufts on the substratum. 

 These develop into small white woolly projections either short and 

 hemispherical or prolonged into horn-like structures, "resembling 

 simple forms of Clavaria" (fig. 2, pi. 56). The end is either rounded 

 or conical. These small bodies are covered with loose tangled hyphae. 

 Later the apex becomes smooth, slightly darker in color, and covered 

 with shorter hyphae. 



Next a single pore appears at the apex (fig. 3, pi. 56), as Hassel- 

 bring (1907) found. Early stages which show the origin of this pore 

 have been difficult to distinguish, as it develops within a few hours 

 after the formation of the buttons or horns, and the loose hairs at the 

 apex screen its first appearance. Longitudinal sections at this stage 

 show first a differentiation of the hyphae just behind the apex (fig. 1, 

 pi. 59). This region stains more deeply than the remainder of the 

 section. The growth at this place is accelerated, and, as increase in 

 size takes place behind the apex, the hyphae at the tip are pulled apart 

 (fig. 2, pi. 59). The hyphae beneath the rupture form a palisade layer 

 which extends laterally into a plane surface (fig. 3, pi. 59). The 

 growth then becomes more rapid at the edge of the layer, producing 

 it outward into a saucer-shaped and later a cup-shaped depression. 

 In this stage it resembles a shiall sporophore of a Peziza (fig. 4, 

 pi. 59). 



In all cases observed by the writer the so-called lamellae have 

 originated upon the surface of this apical cavity (figs. 4-14, pi. 52), 



