310 BOTANY. 



Family 2. Coenogoniei. Canogonium. 



Family 3. Lecideei. Bmomyces, Biatora, Heterotheeium, Zmdea, 

 Buellia. 



Tribe III. Gbaphidacei. 



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

 ciple. Thallus crustaceous. 



Fam.ily 1. Lecanactidei. Lecanactis, Platygraplia, Melaspilea. 



Family 2. Opegraphei. Opegrapha, Xylogra/pha, OrapMs (Fig. 

 215, A). 



Family 3. GlypMdei. Ghiodecton, OlypMs. 



Family 4. Arthouiei. ArtTumia, Mycoporum. 



Tribe IV. Caliciacei. 



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

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

 whicli form a compact mass. 



Family 1. Spliserophorei. SpTimroplwrus, Acroscyplius. 



Family 2. Caliciei. Acolium, Caheium, Coniocyie. 



Tribe V. Vbrhtjcaeiacki. 



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



Family 1. Endocarpei. Endocarpon, Normandina. 



Family 2. Verrucariei. Segesiria, Staurotliele, Trypetlielium, 8a- 

 gedia, Verrucaria, Pyrenula, Pyrenastrum, Strigula. 



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

 modern genera being recorded. 



403.— Order Uredinese. — The Uredineae are related to the 

 foregoing orders of the Ascomycetes, and probably should be 

 gi-ouped with them. They are all parasitic in habit, and the 

 vegetative 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 spores, such apparently distinct forms, that 

 these have frequently been mistaken for distinct plants. 



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

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

 the tissues of the leaves of various plants dense masses of 



