T rue, Notes on the Pliysiology of the Sporopliyte etc. 
39 
of the directive influence of lateral Illumination and the absenee 
of uniformity in Symmetrie illumination, that the radius in which 
the sporopliyte falls in carrying out tliis curvature is determined 
by the direction of the strongest illumination. 
In the hope of getting further light on the question, seve- 
ral attempts were made to carry through to maturity cultures 
in a horizontal position on the klinostat, but unfortunately I was 
balked eacli time by the occasional failure of the apparatus to 
perform its duty. In spite of fliese discouraging features, a pot 
of Mnium capsules was obtained in which, instead of the usual 
pendulous position, an average inclination of 30 0 from the per- 
pendicular was seen at maturity. 
Experiments witli Funarm gave results very similar to those 
above described. The Funaria sporophytes showed themselves 
more quickly responsive to lateral illumination than Mnium. An 
unknown species of Weh er a, found on a somewhat exposed hill- 
side, was more sensitive to the directive influence of light than 
either Funaria or Mnium. 
In view of the partial failure of the klinostat experiments, 
it was deemed desirable to Supplement the observations descri¬ 
bed witli some further evidence to show the relative effective- 
ness of light and gravity in calling forth responses in the spo- 
rophyte, and the following studies were made in the spring of 
1901, ad Harvard University. 
Two experiments were carried out witli Mnium cuspidatum , 
a form found in great abundance in tlie open woods near Ar- 
lington Heights. Colonies of this moss were transplanted March 
22 with the least possidisturbance to flower pots iilled witli wood- 
soil and taken to the greenliouse laboratory at the Botanical 
Grarden. The sporophytes had already made considerable pro- 
gress but were still erect and showed no indication of a capsular 
enlargement. 
In the first experiment, the desire was to ascertain the be- 
liaviour of tlie growing sporophytes when placed in a horizontal 
position with perpendicular illumination. These conditions were 
obtained by sink in g the pot containing the Mnium culture on 
its side in a larger pot filled with sphagnum which was held 
away from the plants by another flower pot placed with its 
mouth over the open end of that containing the moss. Light 
was admitted by breaking out a piece of the empty pot 1 inch 
wide by about 3—-12 inches long. After placing the moss tuft 
in the position described, the containing pot was put in briglit 
diffused light. After forty-eight liours, nearly all of tlie sporo¬ 
phytes had made a more or less marked curvature upwards to- 
ward tlie light. This curvature was some distance from the free 
end of the sporopliyte and seemed to be clearly located in its 
growing zone. Another curvature mucli sharper and more loca- 
lized was .also noted, especially in the more advanced individuals, 
