42 T lue. Notes on the Physiologe' of the Sporophj^te etc. 



In an carly growing .stage. the young sporophytes seem to 

 react .somewhat to gravity in a negative sense, tending to bend 

 u])ward tuward tlie ])erpendicular wlietlifi- liglited from above 

 or froni below. 



In the coiirse of the study of the sporophyte, as above 

 sketched, a numl^er of interesting relation.s were observed per- 

 taining especially to the calyptra. 



"In Fnnaria. the calyptra is a more liighly developed struc- 

 ture than in Milium and seems to perforni so much more per- 

 fectly the ])rotective function which has been assumed for tlie 

 calyptra. This appears reasonable when one bears in mind the 

 natiire of the dangers incident to these two types of moss. Fu- 

 iiaria grows on the ground in dry, exposed sitnations, in tlie 

 füll blaze of the direct sunlight and is exposed during the fort- 

 niffht or three weeks requii-ed for the matiiration of the spores 

 to the danger of desiccation. During the first week after the 

 appearance of the growing archegonium aniong the perichaetial 

 leaves, desiccation is fatal to the young sporophyte, and it is 

 only after the capsular rudiment has reached about one-half uf 

 its mature bulk that it is able to survive the degree of desicca- 

 tion resulting from a few days of hot, dry weather. Hence, the 

 season for sporophyte formation falls in the moist season of the 

 year when the temperature is sufficiently high to allow rapid 

 growth. 



The calyptra is an added factor of great ecological signifi- 

 cance for this moss. 



The archegonium after the fertilization of the egg. groAvs 

 until a length of about 4,2 mm is reached. Separation from 

 the gametophyte results at this stage. and measurements at sub- 

 sequent stages showed that it makes no further growth. It con- 

 sists of three distinct parts: (1) a long, slender, beak-like distal 

 portion comprising, about onehalf of the total length which pas- 

 ses by a somewhat abrupt expansion into (2j an enlarged sac- 

 like portion which in the younger stages is traversed lengthwise 

 by longitudinal folds. This sac contracts sharply at the base of 

 the calyptra into (3) a short, basal, collarlike portion which clasps 

 the seta very tightly. 



The calyptra is a loose bag, drawn togetlicr tiglitly at its 

 mouth in which the entire dividing and growing regions of the 

 young sporophyte are enclosed. Young. still erect, sporophytes 

 from which the calyptrae were removed with the greatest care 

 rarely succeeded in develo])ing into mature sporophytes, even 

 though giving no evidence of injury in the removal. It was not 

 until the capsular rudiment had reached about half its matui'e 

 size that the removal of the calyptra failed to produce untoward 

 effects on the sporophytes. All this seems to point to the great 

 importance of the protection afforded by the calyptra, from mecha- 

 nical injmy as well as from undue desiccation. It seems pro- 

 bable that the removal of the calyptra at the later stages is less 

 detrimental because of tlie increased cuticular development and 



