40 True, Notes on llic Tliysiology of the Sporophyte etc. 



immediately below the calyptra or perha[)S partly wit hin ii. Tliis 

 second ciirvatiiro was, like the first, in the plane of the incident 

 rays. Imt in tlio opposite direction, depn'ssmg the tip of the 

 sporophyte. In many cases. the capsuhir rndinicnt was main- 

 tainod hy tliosi' two ox^josed curvaturos in an appioxiniately ho- 

 rizontal Position. In the more advanced cases, the ends of the 

 sporophytes were pointed ncarly downward. Ihat is, away from 

 the light. 



Twenty-four hours later, the long npward curve of the se- 

 tal portion was semewhat more niarkcd, and in the older indi- 

 viduals in which the capsular rudinients wero furthest advanced, 

 and eonstituted a very well developed, narroMdy elliptical body, 

 the Sharp curve just below the calyptra had so far progressed 

 as to bring the capsular rudiments into a nearly perpendicular 

 Position. In the younger sporophytes the general upward curve 

 brought the distal ends of the sporophytes into a nearly per- 

 pendicular Position. Immediately below the calyptra no curve 

 was Seen. 



On March 29. about 170 hours after the beginning of the 

 experiment, every capsular rudiment, now in most cases about 

 one-half the mature size. hung in a peri)endicular position through 

 a Sharp cui^ve immediately at the base, near the edge of the 

 calyptra. This curvature, in the plane of the incident rays, di- 

 rected the apex of the rudiment away from the light, toward 

 the Center of the earth. The general upward curve was found 

 to have remained as before. 



On April 1, a1)out 240 hours after the beginning of the ex- 

 periment, the capsules, normal and nearly füll sized, were seen 

 in every case to have the sperculum directed downward. The 

 general setal curve had been made permanent l)y tlie internal 

 tissue development. 



Further observations showed that normal capsules developed 

 without any further changes in position. 



From the data described, it seems justiüable to draw the 

 following conclusions: The young sporophyte, prior to the de- 

 velopment of a distinct capsular rudiment. is either positively 

 heliotropic or negatively geotropic, and tends to assume a per- 

 pendicular position which is fixed by the further development 

 of the tissues. When in the young sporophyte a capsular ru- 

 diment has begun to develop. this setal curvature is not mar- 

 ked, possibly because of the rigidity of the seta thi'ough the de- 

 velopment of mechanical tissue. A sharp curvature appears just 

 below the capsule, turning the capsular rudiment into the per- 

 pendicular position as a result of either a positively geotropic 

 or of a negatively heliotropic reaction. It appears that these 

 two opposed responses seen in the two curvatm-es can for a time 

 take place synchronously. The question of the part played l)y 

 light and by gravity is, however, not settled. 



