132 



OEDEE OXLVI. LICHENES. — OEDEE CXLVIII. AIG^E. 



sule somewhat like that of Mosses, but not opening by a lid, and 

 the oalyptra not separating at base, but usually splitting at apes. 

 In fig. 18, Plate III., is seen one of the common forms of the 

 Liverworts. Other forms are flat, veiny expansions, producing 

 sporangia embedded in their fronds. 



CLASS v.— THALLOPHYTES. 



Plants composed solely of cellular tissue, being made up of 

 congeries of cells, or sometimes of single cells, often arranged so 

 as to form a flat expansion, or thallus, but never distinguishable 

 into any proper root, stem, or leaves, or possessing any proper 

 axis of growth. Eeproductive organs usually contained in the 

 substance itself of the plant. 



Order OXLVI. — ^Lichenes. 



Plants consisting usually of flat, crustaceous expansions, which 

 are sometimes long and narrow. Their fructification is in cups, 

 or shields, called apothecia, which are placed sometimes on the 

 surface of the thallus, or immersed in its substance, or in pulveru- 

 lent spots scattered over it. 



These are always terrestrial plants, growing usually on rocks and the barlt 

 of trees. Their most usual forms are Illustrated in fies. 9 and 10, Plato III. 



Order CXLVII.— Fungi. 



These are teri-estrial parasitic plants, destitute of green color, 

 feeding either on living or dead organic tissues, but unable to 

 manufacture organic matter from inorganic. 



They take many forcis, such asEust, Mildew, Smut, and Mould ; two highly 

 magnified forms of the latter being shown in figs. 3 and 4, Plate III. The 

 common Mushroom is the type of another section, illustrated by the edible 

 Mushroom, fig. 12, Plate III. 



Order CXLVIII.— Algae. 



A very large order, or rather class of aquatic, usually mari- 

 time plants, presenting great diversities of form and structure. 

 "While some are microscopic, and consist of but 1 or a few cells 

 aggregated together, others grow to a great size, and show a very 

 distant approach to higher forms. In figs. 1, 2, and 6, Plate III., 

 are seen several of these minute Algae, while figs. 7 and 8 are 

 examples of higher types. 



[Note. — The uses of the different accents and the dash, and all the abhrevi- 

 fttions which are used in the Flora, are explained in the glossary.] 



