1916] Yates: Histology of Calif or niaii Boletaceae 249 



disappears on drying. Even this distinction breaks down in some 

 cases, for certain plants referred to Ceriomyces sometimes have tubes 

 with red months, for example C. auriflammeus. 



Two distinct forms of Suillellus found in the Bay region of Cali- 

 fornia have been referred to a single species (S. Eastwoodeae Murrill) 

 by Dr. Murrill after an examination of dried material. 



Suillellus Eastvv^oodeae ]\rurrill 



Taking ^Murrill's description as a bavsis, S. Eastwoodeae may be dis- 

 tinguished from other species referred to this genus chiefly ])y its size 

 and the shape of the stipe. In SHillellus Eastwoodeae the stipe may 

 be as much as 9 cm. long and 7 cm. thick at the much swollen center. 

 The stipe is contracted at the apex and the base and is perfectly even 

 and glabrous. The plants are solitary. The thick hemispheric pileus 

 may be as much as 10 cm. in diameter. The surface is smooth and 

 glabrous, shining, and not at all viscid. The surface of the pileus is 

 very light brown in color, with an entire, slightly projecting margin. 

 The tubes are adnate or, in old specimens, may separate from the stipe. 

 The yellowish tubes are concave or plane in mass, with small angular 

 pink mouths. The yellowish-brown, smooth, oblong-ellipsoidal spores 

 are 11 to 12.5 by -1 to 5/x. The surface of the stipe is perfectly even 

 and glabrous, concolorous with a rosy tint in certain parts and yel- 

 lowish at the base. The context of the pileus is firm, white or light 

 yellow in color, and changes to blue when wounded Init later it re- 

 turns to its original color. The context of the stipe is yellowish-white. 



The small tubes with red mouths are very characteristic and cannot 

 be readily mistaken in fresh material for any of our other species of 

 Boletaceae, though in dried plants the red color at the mouths of the 

 tubes disappears so that it is almost impossible to distinguish these 

 plants from cei-tain species of ('rrionnicfs except by the slia])e of the 

 stipe. 



Suillellus Eastw^oodeae Form A 



I'late 21, figure 7 



The study of Form A was made upon a single dried specimen sent 

 in from the vicinity of Point Reyes. This specimen agreed in every 

 way witli the published description of N. Eastwoodeae, at lea.st in so 

 far as can be determined from dried material. 



