eluded in other asci. Sporidia are the analogues of seeds, and the 

 medium of the typical propagation of lichens. The excipulum is 

 either of the same color with, and similar to, the thallus (exc. thallo- 

 des); or of different color, and heterogenous nature (exc. proprium). 

 Both are sometimes present ; but hardly ever, typically, are both 

 absent. The excipulum becomes the margin of an open thalamium. 

 It is sometimes suppressed by the growth of the thalamium, and is 

 sometimes scarcely distinguishable from the thallus. 



How the apothecia arise is easily to be seen, but what beside the 

 nisus of nature determines their different evolution it is more diffi- 

 cult to perceive. In part this seems to depend on differences of 

 climate, since many widely diffused species produce apothecia only 

 in peculiar regions; in part, also, it would seem, on light, since 

 apothecia are almost always produced on the upper surface (apoth. 

 antica); and only very rarely on the under side (apoth. poslica). 

 The more imperfect the lichen the more profoundly do the apothe- 

 cia arise: in the Calicia, the Verrucarise, &c., even below the crust 

 and in the matrix itself; in very many, in the medullary layer; and, 

 in those best developed, even in the cortical layer. We have hence 

 apoth. immersa and superficialia ; innata, adnata; sessilia and ehvala. 

 The fulcrum of apothecia is either formed of the excipulum thai- 

 lodes (podicellus; apoth. podicellata), or of the excipulum proprium 

 (stipes; apoth. stipitata). 



The typical form of apothecia is round, but oblong and linear 

 apothecia occur normally, and these last by composition become 

 ramose (apoth. lirellazformia}. An excipulum proprium which is 

 typically closed we call perithecium, as in Verrucaria. Besides 

 these, we distinguish apothecia which are deeply excavated, with a 

 contracted margin (apoth. urceolctta) ; those slightly concave, with 

 an elevated margin (apoth. sculelliformia) ; those dilated, flat, with- 

 out prominent margin (apoth. peltceformia) ; those convex, in which 

 the margin is repressed (apoth. cephaloidea); those between scutel- 

 late and peltaeform (apoth. disciformia) ; and those between scutel- 

 late and cephaloid (apoth. tuberculata). 



All apothecia are primarily closed, the included thalamium being 

 conglobate, gelatinous-waxy, and the asci converging (apoth. nuclei- 

 forme). If the apothecia remain closed, the nucleiform thalamium 

 deliquesces, and the sporidia escape through an ostiole, which is 

 either a simple pore, or one at the summit of a papilla. If the apo- 

 thecia themselves gape open, the thalamium is either flattened into 

 a rigid and persistent lamina (apoth. subdisciforme), or shortly after, 

 itsel f collapses into a powdery mass. If, finally, the nucleiform state 

 of the thalamium is so quickly concluded that the lamina appears 

 originally open, with not even connivent margins, which occurs es- 

 pecially in apothecia produced from the cortical layer, wherein a 

 punctiform disk shows itself before the excipulum is formed, we 

 have a third kind (apoth. apertum). 



Among those lichens which have closed apothecia (Angiocarpi), 

 many thalamia are sometimes included in a single excipulum (apoth. 

 composita], and again many are sometimes confluent in one. In 

 like manner, among the lichens with open apothecia (Gymnocarpi), 



