CHAP. III. ALG^. 231 



16. Pulviluni, are spongy, excrescence-like bodies, sometimes 



rising from the thallus, and often resembling minute 

 trees, as in Parmelia glomulifera. Greville. 



17. Cyphellce, are pale tubercle-like spots on the under surface 

 of the thallus, as in Sticta. Grev. 



18. LacuncB, are small hollows or pits on the upper surface of 



the thallus. Grev. 



19. Nucleus proligerus, is a distinct cartilaginous body, coming 



out entire from the apothecia, and containing the spo- 

 rules. Grev. 



20. Lamina proligera, is a distinct body containino- the 



sporules, separating from the apothecia, often very convex 

 and variable in form, and mostly dissolving into a gela- 

 tinous mass. Grev. 



21. Fihrillce, are the roots. 



22. JExcipulus, is that part of the thallus which forms a rim 



and base to the shields. 



23. Nucleus, is the disk of the shield which contains the 



sporules and their cases. 



24. Asci, are tubes, in which the sporules are contained while 



in the nucleus. 



25. Tliallodes, is an adjective used to expi-ess an origin from 

 the thallus : thus, margo thallodes signifies a rim formed 

 by the tliallus, excipulus thallodes a cup formed by the 

 thallus. 



26. Lorulum, is used by Acharius to express a filamentous, 



branched thallus. 



27. Crustay is a brittle crustaceous thallus. 



28. Gongyli, are the Granules contained in the shields, and 

 have been thought to be the sporules by which lichens 

 are propagated : but this is doubted by Agardh. 



8. AlgcB and Ckaraeece. 



These, with fungi, constitute the lowest order of vegetable 

 developement : they vaiy in size from mere microscopic ob- 

 jects to a large size, and are composed of cellular tissue in 

 various degrees of combination ; some are even apparently ani- 

 mated, and thus form a link between the two great kingdoms 

 of organised matter. Their sporules are either scattered 



Q 4 



V 



