40 ANNALS OF SCOTTISH NATURAL HISTORY 



surface. The cup continues to enlarge ; and the central hole 

 widens, remaining circular and still surrounded by an entire 

 inflexed margin, so that the brown hymenium lining the 

 interior is in full view. When the cup has reached a diameter 

 of about an inch it has assumed the form figured in Cooke's 

 " Mycographia," figures 100, 373. The margin becomes 

 split rather irregularly by the more rapid growth of the 

 adjacent tissues ; and the cup becomes turbinate. The pro- 

 portions of the cup vary a good deal. I have found them 

 in this stage upwards of i^ inches (42 mm.) in diameter. 

 The tissues lining the cup continue to increase ; and at last 

 the hymenium may become only slightly concave, or flattened, 

 or even slightly convex, so as to resemble greatly Pczisa 

 ancilis, Rehm (a species that I have found in Aberdeenshire 

 in April on ground covered with old sawdust). In this con- 

 dition I have found examples exceeding 2^- inches (60 mm.) 

 in breadth. P. ammophila thus passes through so marked 

 changes of form that, in the later stages especially, it might 

 readily be mistaken for some other species if only one or two 

 examples were found. The long stalk buried beneath the 

 sand is one of its most characteristic features ; but, as already 

 stated, this is so easily broken off that it might readily be 

 overlooked. 



The depth to which the plant is imbedded in the sand 

 depends very much on circumstances, after the cup has pushed 

 its way out and has opened up. It may remain sunk up to 

 the very edge of the cup ; and even the cup may be found 

 partially or wholly filled with drifted sand. But frequently 

 the cup and even a part of the stalk rise above the level of the 

 sand, probably owing to the latter having been blown from 

 around them by the wind. On tracing the stalk downwards 

 one finds that it usually remains unbranched ; but in some ex- 

 amples it gives off two or three short, thick, diverging branches. 

 The asci are cylindrical with rounded apex. They are usually 

 about 300 to 350 mm. long by about 15 mm. wide. Each 

 contains eight elliptical, smooth, colourless sporidia, which 

 vary from 15 to 20 mm. long by 8 to 10 mm. broad. They 

 escape from the ascus by a well-defined circular hole at the 

 apex. The paraphyses are not numerous. They are slender 

 and unbranched, and are slightly thickened towards the apex. 



