310 BOTANY. 



Family 2. Coenogoniei. Cxnogonium. 



Family 3. Lecideei. Boeomyces, Biatora, Heterothecium, Zeddea, 

 Buellia. 



Tribe III. Gkaphidacei. 



Apothecia of various forms, frequently lirelliform, in a proper ex- 

 ciple. ThalluB crustaceous. 



Fam.ily 1. Lecanactidei. Lecanactis, Plalygrapha, Melaapilea. 



Family 2. Opegraphei. Opegrapha, Xylographa, OrapTiis (Fig. 

 315, A). 



Family 3. Griyphidei. Okiodecion, Glyphis. 



Family 4. Arthoniei. Arthonia, Mycopurum. 



Tribe IV. Caliciaobi. 



Apothecia turbinate-lentiform or globose, frequently stipitate, mar- 

 gined by a proper exciple, tlie disk breaking up into naked spores, 

 which form a compact mass. 



Family 1. Sphserophorei. Splimrophorus, Acroscyphus. 



Family 2. Caliciei. AeoUum, Calicium, Conioeybe. 



Tribe V. Vbrrucabiacei. 



Apothecia globose, in a proper exciple, becoming pertuse with a pore. 



Family 1. Endocarpei. Eiidocarpon, Normnndina. 



Family 2. Verrucariei. Segesiria, Staurotfiele, Trypethelium, Sa- 

 gedia, Verruearia, Pyrenula, Pyrenastrum, Strigula. 



(d) Fossil lichens are extremely rare, only a few Tertiary species of 

 modern genera being recorded. 



403.— Order TJredinese. — The TJredinese are related to the 

 foregoing orders of the Ascomycetes, and probably should be 

 grouped with them. They are all parasitic in habit, and the 

 vegetatire portions of the plant-body are greatly reduced, 

 leaving but little more than the organs of reproduction. 

 Their life-history is but imperfectly known, and nothing is 

 yet known as to their sexual organs. They are generally 

 polymorphic — that is, they assume, in their production of 

 various kinds of spofes, such apparently distinct forms, that 

 these have frequently been mistaken for distinct plants. 



404. — So far as made out, the life-history of the TJredinese 

 appears to be about as foUovvs : In the spring there appear in 

 the tissues of the leaves of various plants dense masses of 



