True, Notes 011 tlie Physiology of theSporophyte etc. 
35 
Experimental. 
I have given attention especially to the development of the 
sporophyte of two of our commoner species, Funaria hygrome- 
trica Sibth., cliaracteristically fonncl in exposed, snnny spots, and 
Mnium cuspidatum Hedw., one of the shade-loving mosses of the 
woods. In its matnre form, the capsule of Funaria is bilaterally 
symmetrical and decidedly arcuate, being convex in its upper 
outline, concave beneath. In addition to this curvature of the 
capsule, the seta shows a very pronounced bend some distance 
below the capsule. The capsule of Mnium cuspidatum is nearly 
radially symmetrical and takes a pendant position by means 
of a sharp curvature of the seta formed very the capsule. 
Early in April, turfs of both species were transplanted into 
pots and removed to tlie laboratory for study. The general 
course of development is much the same in both species. Fol- 
lcrwing tlie fertilization of the egg, both the archegonium and 
tlie young sporophyte begin growth, the latter as a slender body 
enclosed in the rapidly enlarging archegonium. At this stage 
the tip of the calyptra may just be seen among the perichaeti- 
cal leaves. Soon the growth of the archegonium ceases, and this 
organ is torn away froin its attachment by the elongation of 
the sporophyte enclosed witliin it. Goebel (3) suggests that the 
line at wliicli the archegonium separates from the receptacle is 
marked by a zone of modified, weakened tissues to facilitate the 
rupture. In a number of iiistances,' specimens of Funaria were 
seen in which the calyptra failed to separate as usual at the 
base, and the sporophyte pierced it, growing up through it in a 
manner recalling the Hepaticas. This would seem to indicate 
that occasionally the specialized, weakened zone may still fail to 
tear with the required readiness. The sporophyte continues to 
grow in length for about a fortnight under laboratory condi- 
tions, keeping an erect position. Einally, as the seta reaclies 
nearly the normal length, the curvature begins to appear at the 
base of the calyptra. Before the curvature of the seta is com- 
plete, but usually not until it is well under way, the rudimen- 
tary capsule can be detected as a small swelling just below the 
distal extremity of the sporophyte. This structure now enlarges 
rapidly while growth in the seta rapidly diminislies and soon 
altogether ceases. The calyptra is finally ruptured by the ex- 
pansion of the growing capsule and falls away. The capsule of 
necessity retains permanently the position assumed at the time 
tlie narrow, elongating zone below the capsular rudiment loses 
the power of growth. 
It was first necessary to become oriented in regard to the 
rate and distribution of growth in tlie sporophyte at tlie diffe¬ 
rent stages of its development. For this purpose, Funaria was 
given most study since it is known to bear hard treatment more 
easily than many otlier species. India ink dots were placed at 
intervals along the sporopliytes and the intervening distances 
3* 
