306 



if not quite, sessile liymenium, flat-bowl-sliaped, whitish or flesh- 

 tinted widiout, and rufous witliin. There Is a decided margin to 

 tlie bowl, formed of closely compacted hyphae, as in some Cor- 

 ticia, and the hymcnium itself, when ripe, ceases to be hard and 

 smooth, and becomes powdery from the escape of the ripened 



spores. 



The difficulties attending the study of this interesting fungus, 

 Michcncra Artocreas, B. & C, have been great. Its rarity, 

 combined with its remarkable structural peculiarities, have been 

 the cause of many confusions of nomenclature, and each student 

 seems to have taken pleasure in re- naming this form. Berkley 

 and Curtis seem first to have specifically described it in their 

 ''Cuban Fungi" under the name oi MicJienera Artocreas ; but 

 subsequent writers have variously styled it Artocreas Michcncri, 

 A. Michcncra^ Aleurodiscus Michenera, and A, Michcncri In 

 addition to the confusion in synonomy, the necessarily imperfect 

 descriptions of the earlier botanists have been accepted without 

 thorouHi verification, atid from this source have come some of 

 the errors which I hope to disprove in this paper. 



For the sake of clearness, I will begin my description with 

 the young hymcnium. It is made up of simple paraphyses, long, 

 slender, and smooth, unicellular, erect, parallel and tolerably 

 close together. Immediately beneath them, that is, at the base 

 of the hymcnium, are the ordinary mycelial hypha^ of the plant, 

 running horizontally or obliquely and interlacing among them- 

 selves. It is, of course, from these that the paraphyses spring. 

 Presently the tips ot some of the hyphae become erect, swell, and 

 force their way upwards between the paraphyses. The swollen 

 tip becomes more granular than the rest of the hypha. Later 

 each tip is divided off by a cross partition (see fig. k, Michcncra 

 Artocreas, B. & C ) ; it increases in size; its walls become thick- 

 ened, and at the same time, by the contraction of the upper part 

 of the cell, a long, tapering, lash-like structure is formed at the\ 

 topmost point. Finally, the neck of the tip-cell, which has now 

 'grown to be flask-shaped, is closed by the thickening of its w^alls. 



In the meantime, within the cell thus produced at the outer 

 end of a hyphal thread, a spore has been forming. This spore is 

 large, granular, and either colorless or faintly flesh-tinted. When 



