1893.] NATURAL SCIENCES OF PHILADELPHIA. 365 



with mingled half rings and blunt spines. Spores dull gray (not 

 cinereous) in mass, colorless with reflected light, 7 - 5 to 8// in 

 diameter ; epispores very thin showing under a high amplification 

 from 10-12 isolated irregularly scattered hemispherical papilla?. 



A. magna var. rosea. 



Capillitium equally long as in the previous form, but less robust 

 in habit and more cylindric in shape : color of capillitium and 

 spores bright rose-red when recent ; sculpturing of spores and 

 capillitium like that of the previous form ; calyculus smooth ; spores 

 7'5fi in diameter. 



Fairmount Park, Philadelphia, Pa. 



The association of these two forms under one specific head is 

 justified by the history of the species considered in connection with 

 the fact of the essential accordance of the characters of the two forms 

 in their totality. 



The robust gray form was first found by the writer, growing 

 separately. A few days later it was found again on the same log 

 with clusters of the red form growing beside it. One month later in 

 another locality about a mile from the first, an extraordinarily large 

 growth of the gray form in large effused masses w r as found by Mr. 

 H. "Win gate, also associated in a similar manner with clusters of the 

 red variety. In neither instance was there any intergrading of 

 colors, nor did any of the clusters contain individuals of both colors- 

 While these parallel histories might be considered as mere coinci- 

 dences, the correspondence of all the essential specific characters of 

 the two forms has led the writer to the belief of their specific connec- 

 tion at least, although not necessarily of their development from the 

 same plasmodium. 



This species is allied to A. nutans in the relaxed elongated capil- 

 litium, but differs from it in the sculpturing of the capillitium and 

 calyculus. The capillitium-threads lack the minute vein-like retic- 

 ulation which covers the interspaces between the coarser half rings 

 and spines in A. nutans. 



The calyculus of the red form is absolutely smooth except the lon- 

 gitudinal plications common to the eu-arcyrise. In the gray form it 

 is practically smooth, there being but a few isolated spinules on its 

 inner surface. In A. nutans, however, the inner surface of the 

 calyculus is covered with an exquisitely beautiful sculptured reticula- 

 tion, coarse and venose below but grading above into a fine net with 

 polyhedral meshes sometimes having spinous prolongations project- 

 ing inwardly from the intersections. 



