3^16] Yates: JUstologij of Californian Boletaceae 233 



genus Eostkovites and will be taken np in some detail wIkmi we eome to 

 the consideration of this genus. 



Special Histology 



The species and forms discussed below have all been either deter- 

 mined by or verified by Dr. AV. A. ]Murrill. Tliey have, however, all 

 been carefully studied by myself, and the segregation of forms result- 

 ing from differences in histology or morphology in the plants under 

 consideration has been made by the writer. 



CERIO:\IYCES Batt. 



The genus Cerioniyccs as limited by ]\Iurrill contains some forty- 

 nine species occurring in North America. Hence it contains by far 

 the largest number of North American species of any of the genera 

 of Boletaceae. 



According to ]\Iurrill, the genus Ceriomyces is made up of annual 

 terrestrial plants with ochraceous or yellowish-brown, smooth, oblong- 

 ellipsoidal spores. The stipe is central and exannulate. The surface 

 of the stipe is either even or reticulate. The stipe is solid except in 

 one or two species. The pileus is dry or rarely viscid and may be 

 either glabrous or variously ornamented. The context is usually white 

 or some shade of yellow and may be sometimes tinged with other 

 colors. The tubes are either free or adnate, small and eylindric or 

 often large and angular near the stipe. A few species are reported 

 to be poisonous. 



Ceriomyces is a genus of negative characters. It differs from other 

 Boleti with ochraceous or brown spores which lack a radial arrange- 

 ment of the pores by the following negative characters. It differs 

 from the genus SuilleUiis by the absence of red mouths to the tubes; 

 from Rostlcovites it differs by the absence of glandular dots on the 

 stipe; and from the genera Boletus, Boletellus, r](lv(voholetiis, and 

 Strobilomyces it differs by the absence of an aniiuhis. 



It iii;i.\- be remarked here concerning the presence or absence of a 

 transverse veil that there seems to be a lack of definite information. 

 The general statement, for example (Mui-rill. 1010). is lluit the species 

 of Ceriomyces are exannulate. So fai- as my own experience goes, 

 this statement is undoubtedly true, but as to the presence or absence 

 of a veil the evidence is not so clear. The condition of things in 

 regai'd to the presence of a veil in the Boletaceae is similar in a way 



