INTRODUCTION TO CRYPTOGAMIC BOTANY". 329 



except so far as it was shadowed out in j^cidiuon and Rwdelia. 

 In Cystotricha we have a Torula growing from a sort of hyme- 

 nium, and in Bloxamia we have a SporoscJdsma (Loth on a 

 reduced scale) in the same position. In Phragmotrichum (Fig. 

 74, c), the spores are very singular in form. Seiridium may 

 be compared with Alternaria. Piltdium and Excifula are 

 better, perhaps, placed in the next group. Bloxamia (Fig. 

 74, h) is curious, because the disc consists of close-packed 

 threads containing quadrate spores. When the lid of the peri- 

 thecium falls it carries with it the tips of these threads, the con- 

 tents of which are then exposed. The evident relation between 

 Bloxamia and Sporochisma, as well as many peculiarities 

 about the plant, forbid the junction of the former with Asco- 

 mycetes, to which it bears a close analogy. The plant is, how- 

 ever, very minute, and requires careful examination. It should 

 be observed that there are several genera of precisely similar 

 habit, and closely agreeing in external character, so as to make 

 the determination in some measure doubtful without actual 

 microscopic inspection. How far these may be distinct auto- 

 nomous plants, for one of them at least, Xylograplia parallela, 

 bears perfect asci, must be left to future observation. Myxor- 

 mia is remarkable for its exposed disc. The perithecium or 

 excipulum, for perhaps it is never closed, is here composed of 

 erect, laterally confluent threads whose tips are free and obtuse. 

 The geographical limits of the genera are at present unknown. 

 They have hitherto been found only in Europe and the United 

 States. 



5. Melanconiei, Corda. 



Mycelium or stroma forming a distinct cushion, from which 

 the fertile threads or sporophores spring ; spores various. 

 Perithecium wanting. 



354. This division is distinguished by its abundant spores, 

 frequently oozing out in vast quantities from the receptacle, 

 for there is no perithecium, and either forming black stains 

 round the orifice, or a distinct globule or tendril, according 

 to the quantity of mucilage which accompanies them. The 

 spores vary very greatly in appearance and character. They 

 may exhibit bright tints of pure red and yellow, or may be 



