358 



BOTANY. 



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

 Europe. 



Order Andrseaceae. — In this small order the little plants of which 

 it is composed have a sliort-stalked sporogonium.ridsed upon a pseudo- 

 podium, as ill the Sphagnacem ; the sporogonmm 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 Jungermanniacem. In the growth of the sporogonium 

 the old archegonium 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- 



„. „.„ „ .1 t^ . cells, much as in the next order. 



Pig. 2i6.—Fitnana hygrometnca. A, ' ,..-,. , , 



a younj; leafy plant, g, with Bporogo- The capsule is indehiscent, and the 

 niiim St 11 covered with the calyptra, c. „„„rp„ „.„ _.* f^pp nnlv bv its dpfnv 

 S, leafy plant, g, with nearly ripe spo- Spores are set tree only Dy its aecay. 

 ro^oniiim, /,• o, the calyptra ; s, seta. The old archegonium persists as a 



C, longitudinal section of a capsule ; i + „ ? +i ,... 



c, c, cSlumella ; d, operculum or lid, calyptra covering the capsule, 

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



6pore'^bea?tag"laye?;'^'a?rTa'ri"'^sH?- ■»™. Phnscum, and Bruchia. The 



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



confervoid filaments ; ^, inferior con- . 



n<*ctionof the columella with the tissues annuals. 



of the capsnle. ^ and .B slightly mag- j^ the Tertiary (Miocene) of Eu- 



nified ; V about 40 diameters.— After j, ., . , 't., 



Sachs. rope a fossil species of j'hascum has 



been found. 



Order Bryacese. — 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- Bryacese clearly stand at the head of the Bryo- 

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



