53 



THE FAMILIES AND GENERA OF THE S. A. MOSSES*. 



Order I. SPHAGNALES. 



Wall of archegonium splitting during the development of the sporogonium 

 and remaining at its base as a vaginula : sporogone (capsule) supported by 

 a ftsettdoftodiwwi which does not originate from the archegonium, but 

 from the twig that carried it. Calyptra absent or rudimentary. Capsule 

 opening with a lid. No peristome. Fam. i. 



Order II. ANDREAEALES. 



Sporogonium with vaginula, pseudopodium and calyptra. Capsule 

 opening by means of 4 — 8 longitudinal slits. Fam. 2. 



Order III. BRYALES. 



Sporogonium provided with vaginula and calyptra and generally borne on 

 a true seta. Capsule opening by means of a lid, its mouth mostly with a 

 peristome. 



I. Subord. Eubryineae. 



Teeth of peristome formed of the thickened walls of cells, transversely 

 articulated. 



Series 1. Haplolepideae. 



Peristome simple (rarely quite absent). The dorsal (outer) layer of the 

 teeth formed of one row of cell-walls, the ventral (inner) layer of two rows. 



Fam. 3 — 9. 



Series 2. Diplolepideae. 



Peristome double, rarely apparently simple or rudimentary. Dorsal layer 

 of exostome formed of two rows of walls, ventral layer of one row. 



Fam. 10 — 31. 



II. Subord. POLYTRICHINEAE. 



Teeth of peristome consisting of entire, more or less elongated, horseshoe- 

 shaped cells, which are slantingly articulated. Fam. 32. 



* By V. F. Brotherus (Helsingfors). 



