738 MINNESOTA BOTANICAL STUDIES. 



ined. Within the layer of idioblasts the cortical cells become 

 smaller on each side of the pith plate. This latter is composed 

 of anastomosing filaments with occasional trumpet-hyphas and 

 does not differ particularly from the same tissue as displayed in 

 the stipe. The cortex of the mid-lamina and of the pinnae 

 seems to show some fairly constant differences. In the pinnae 

 the cells are often uniformly larger and the layer of idioblasts 

 is frequently almost continuous. 



The sorus. I do not find anywhere in the literature of Ptery- 

 gophora an account of its fruiting area. The first fruiting ma- 

 terial that reached me was collected near Port Renfrew by Miss 

 Josephine E. Tilden during December, 1901. Shortly after- 

 wards Professor Setchell kindly sent me some dried pinnae col- 

 lected at Whidby Island, Washington, by Mr. N. L. Gardner, 

 and said to display sori. My observations are made from the 

 fresh material collected by Miss Tilden. The soral patches 

 occur upon the lateral pinnae and not upon the mid-lamina. In 

 this respect they remind one of the eoral distribution of Alaria ; 

 but while in Alaria the entire pinna, except a very small mar- 

 ginal region, is soriferous, in Pterygophora the sori form some- 

 what irregular patches upon both surfaces of the pinna and 

 much of its area fails to develop them. In this respect Ptery- 

 gophora approaches more nearly to Laminaria. 



The sori are composed of numerous elongated, saccate goni- 

 dangia, each bearing from fifty to two hundred spherical go- 

 nidia. The gonidangial surface is surmounted by the inter- 

 mingled paraphyses, averaging half as long again as the 

 gonidangia and their clavate distal ends capped with cuticular 

 masses, suggesting those already described for Lessonia and 

 indicating that in this plant, as in Lessonia, the cuticular layer 

 does not separate in a plate, as described for Laminaria by 

 Thuret and as known to occur also in Nereocystis, but divides 

 into individual paraphysal calyptra. Some gonidangia meas- 

 ured indicated an average length of 50 mic. and diameter of 

 10 mic. The gonidia are nearly 2 mic. in diameter and in a 

 double-stained preparation, made for me by Mr. H. L. Lyon, 

 take Delafield's haematoxylin while the paraphyses and cutic- 

 ular substance take the safranin. The gonidangia and para- 

 physes stand upon a floor-layer such as is found in all Laminaria- 

 ceous sori, and their development does not differ from that 

 which has already been described for other genera. 



