AGARICALES 457 



genus. In H. (Camarophyllus) virgineus (Bauch, 1926) both four- and 

 two-spored races are formed. The four-spored races develop normally 

 with clamp connections and binucleate mycelia, while the two-spored 

 race is always uninucleate and develops parthenogenetically. The 

 haploid chromosome number is four in both races. 



The basidiospores are smooth and hyaline except in Gomphidius 

 where they are dark. Their germination was followed in Nyctalis 

 asterophora (N. ly coper doides) and N. parasitica parasitic on Russula 

 and Lactarius (Brefeld, 1889). In these, they develop to mycelia which 

 under certain nutritive conditions, produce oidia capable of immediate 

 germination. In time, oidial formation disappears and is gradually 

 replaced by thick-walled, brown or ochraceous gemmae which are rich 

 in reserve materials. In N. parasitica the gemmae are mostly intercalary 

 and smooth, and in N. asterophora they are terminal and echinulate or 

 verrucose. They are liberated by swelling of the intermediate cells. In 

 natute, they are formed in the lamellae in N. parasitica and in the periph- 

 eral layers of the pileus in N. asterophora. They are produced in 

 such numbers that the lamellae below the pileus are stunted or only 

 suggested, and never mature. In small individuals, the fundament 

 of the fructification does not extend much above the thick mass of 

 gemmae which have an odor like that of rancid meal. Under suitable 

 cultural conditions, the gemmae may germinate to mycelia. 



Agaricaceae. — This family differs from the Hygrophoraceae by the 

 higher development of its thin lamellae; the trama becomes very thin 

 so the lamellae consists mostly of the two hymenia. Otherwise, the 

 characters are mostly negative. To this family are assigned all those 

 forms which for lack of special characters cannot be placed in the other 

 families. In this sense, they include at least eight thousand species 

 which one, according to his taste, may divide into a varying number 

 of tribes and genera. Five of these tribes with about two dozen genera 

 are briefly discussed. 



The Clitocybeae or Collybieae form a direct continuation of the 

 Hygrophoraceae. They are also strongly reminiscent of the Cantharella- 

 ceae and Dictyolaceae and pass over so gradually that Clitocybe auranti- 

 aca is often considered a species of Cantharellus. Their fructifications 

 are fibrous or fleshy, their lamellae are membranous; in part these are 

 still decurrent and in the majority of species are exogenous, as in Hygro- 

 phorus. In others, however, as in Gomphidius, they are formed endoge- 

 nously within a partial veil. The first-named type was shown for Mycena 

 subalcalina, Entoloma fiavi folium (Douglas, 1918), Omphalia chrysophylla, 

 Clitocybe cerussata, Clitopilus noveboracensis (Blizzard, 1917) and Pluteus 

 admirabilis (Walker, 1919), Collybia tuberosa&nd C. velutipes (Moss, 1923), 

 Mycena pterigena, M. sanguinolenta, M. codoniceps (Kuehner, 1926), 

 and the latter type for Clitocybe laccatus (Laccaria laccata) (Beer, 



