i 4 
F. Cavers. 
at all may be produced after the first one. The archegonium 
resembles that of the Bryales in structure ; it has a thick stalk and 
the neck-cells are in spiral rows. It has not been determined with 
certainty whether it grows by means of an apical cell, as in 
Bryales. 
The embryogeny of Sphagnum presents some interesting 
features. The first division of the fertilized egg is into an upper 
(epibasal) and a lower (hypobasal) cell, but the further development 
differs from that seen in Bryales and recalls the embryogeny of the 
Jungermanniales ; the hypobasal cell undergoes a few irregular 
divisions, while the epibasal cell divides repeatedly by transverse 
A 
Fig. 65. Sphagnum compaction. Three stages in development of embryo 
sporophyte. 
walls to form a row of about six cells (Fig. 65). As in Junger¬ 
manniales, each of these cells divides into quadrants and then by 
tangential divisions a series of inner cells (endothecium) is 
separated from a layer of outer cells (amphithecium). The embryo 
soon becomes pear-shaped (Fig. 66), the narrow upper portion 
eventually producing the capsule, while the lower portion for a 
time grows much more rapidly and forms the swollen haustorium; 
at this stage the embryo strikingly resembles that of Antho- 
cerotales, except for the absence of the meristem zone. The 
archesporium is dome-shaped and arises, as in Anthocerotales, 
