232 TJnivcrsiiij of California Puhlications iu Botany [Vol. 6 



of the tubes, branching and curving outward toward the hymenial 

 layer, whose basidia, paraphyses, and cystidia (when present) are 

 formed by the swollen tips of these hyphae. 



The basidia are club-shaped structures with four projections at 

 the tips known as sterigmata. From each sterigma a single spore is 

 abjointed. Along with the basidia we find other club-shaped struc- 

 tures known as paraphyses. The paraphyses are usually somewhat 

 shorter than the basidia but, like the latter, they are formed by the 

 club-shaped, swollen tips of the hj-phae. They differ from basidia 

 only in their usually somewhat smaller size and by the absence of 

 sterigmata. The paraphyses are probably merely sterile or possibly 

 immature basidia and originate in the same manner. The function 

 of the paraphyses is unknown. They tend, perhaps, to keep the basidia 

 apart and thus give the spores more space in which to develop. 



In addition to the basidia and paraphyses, structures known as 

 cystidia are found in a few species of the Boletaceae. Except in species 

 of Bostkovites, which will be described later, the cystidia are few in 

 number and are easily overlooked. They are usually more or less club- 

 shaped or cone-shaped and project for some little distance out from the 

 hymenium towards the center of the tubes. The function of the cystidia 

 is unknown. De Bary suggests the theory that the cystidia belong mor- 

 phologically to hair-structures and that they may serve to protect the 

 basidia. He states, further that in some species of Coprinus, one of 

 the black-spored Agaricaceae, the cystidia extend across the space be- 

 tween the gills and, in this instance, appear to serve the function of 

 keeping the spore-bearing surfaces of the gills from coming in con- 

 tact with each other. No such function for the cystidia appears prob- 

 able in the case of the Boletaceae. In none of the plants that I have 

 examined do the cystidia project above the hymenium more than a 

 very small fraction of the diameter of the tubes, so that they never 

 approach the opposite side of the tubes. 



In species of Bostkovites we find certain peculiar structures re- 

 sembling cystidia in certain respects and which for lack of a better 

 term may be designated as "glands." These "glands" are found in 

 clusters or nests, both in the tubes and on the surface of the stipe. 

 They excrete a whitish liquid, which may be seen in j^oung specimens 

 adhering in drops to the mouths of the tubes and on the surface of the 

 stipe. This liquid becomes black when dry and then takes the form of 

 black granules. The "glands" seem to be quite characteristic of the 



