358 



BOTANY. 



The genus Sphagnum was represented in the Tertiary (Miocene) of 

 Europe. 



Order Andreeacese. In this small order the little plants of which 

 it is composed have a short-stalked sporogonium, raised upon a pseudo- 

 podium, as in the Sphagnacece ; the sporogonium contains a layer of 

 spore-forming tissue, disposed as in the preceding order ; but the ripe 

 capsule opens by splitting into four longitudinal valves, in this remind- 

 ing one of the Jungermanniaceoe. In the growth of the sporogouium 

 the old archegoniuui is torn away at its base, and carried up as a cap 

 (calyptra), which covers the apex of 

 the capsule. 



The principal genus is Andrcea, 

 represented in the United States by 

 a few alpine or sub-alpine species of 

 brownish or blackish rock - loving 

 Mosses. 



Order Phascacese. These small 

 Mosses are peculiar in having but 

 a little development of leafy axis, and 

 in their persistent protonema. The 

 sporogonium is short-stalked, or ses- 

 sile, and the pseudopodium is very 

 short, or entirely wanting. The 

 spores are, in the simplest genus (Ar- 

 chidium), developed from a single 

 mother-cell, while in the higher ones 

 they develop from a layer of mother- 



. , f 8 ' mucb as . in , ^ next / d f' 

 a young leafy plant, g, with sporogo- The capsule is indelnscent, and the 



^aV^ "l*> are set free only by its decay. 

 c, thecalypira; . seta. The old archegonium persists as a 



^Stt^K cal ^ tra rin * the capsule. 

 which will separate from the remainder The principal genera are Archidi- 

 of the capsule at a; , peristomc- ; , n , i r> ? mi 



spore-bearing layer ; i, air cavity inr- , PkiKum, and Bniefna. The 

 rounding the columella, and crossed by species are terrestrial, and many are 

 confervoid filaments ; t, inferior con- r . 

 n -ctionof the columella with the tissues annuals. 



Sachs. rope a fossil species of fhatcum has 



been found. 



Order Bryaoese. The plants of this order constitute the true 

 Mosses. They are usually bright green (in a few genera brownish), 

 and in the great majority of instances live upon moist ground and 

 rocks, or upon the bark of trees ; in a comparatively small number 

 of cases the species live in the water. 



In the development of their tissues and the complex structure of 

 their sporogonia the Bryacear clearly stand at the head of the Bryo- 

 phyte Division. The tissues, as indicated above (paragraph 458), attain 



