358 



BOTANY. 



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

 Europe. 



Order Andrseacese. 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 Jungermanniacece. 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 Andrma, 

 represented in the United States by 

 a fiw 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- 



... A, cells - mucb as in tlie next order - 

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

 nium st 11 covered with the calyptra, c. sr . npps , - * <_ nn i v u v ; t ~ ^ Pft ^ 

 , leafy plant, g, with nearly ripe spo- s onlv J lts decay, 



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

 C, longitudinal section of a capsule : , ,1 , 



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

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

 of the capsule at a ; p, peristome : s. , 3 n 7 mi 



spore-bearing layer ; h, air cavity sur- *, Phuscum, and Brucliia. The 

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

 confervoid filaments ; t, inferior con- 

 nection of the columella with the tissues annuals. 



^rTMV&iSEKS Iu the Tertia 7 ( Miocene ) of Eu - 



Sachs. rope a fossil species of Phascum has 



been found. 



Order Bryaceee. 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 Bryaceae clearly stand at the head of the Bryo- 

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



