32 HUMPHREY 



fruiting organs quite as advanced as those of 1 argioni'a or 

 Fimhi'iar'ia. As for Cryplomt't?'tum, it is not surprising to find 

 so few antheridia, for even as late as the first week of February 

 sections of Cryfto^niti'mm revealed the presence of mature 

 antheridia while in the case of Fimbriaria they may be found 

 almost ripe before the beginning of the wet season. Abrams ' 

 in his studies of Cryftomitrmm found that the antheridia 

 matured earlier than the archegonia and informs me that he 

 found fairly well advanced stages of the antheridium as early 

 as November. In Porella not only all stages in the develop- 

 ment of sex organs are to be found but well-developed sporo- 

 phytes as well. This accounts for the very sudden appearance 

 of mature sporophytes shortly following a few days of wet 

 weather. Growing as it ordinarily does on the exposed sur- 

 faces of rocks and tree trunks, it is liable to severe exposure 

 and may be left quite dry in a few hours of wind or sunshine. 

 This fact may have some influence upon its reproductive habits 

 and, in a measure, account for the advanced sporogonia found in 

 revived mxaterial. At any rate Porella is scarcely to be com- 

 pared with such thallose forms as Riccia or Targionia. The dif- 

 ferences in habit and structure might well beget differences rela- 

 tive to the appearance and time of development of the sex organs. 



In another part of this paper the writer mentions having 

 found Fossombronia longiseta so situated out of doors as to re- 

 ceive a constant supply of moisture from a leak in a water 

 pipe. Many of these plants were examined on November i 

 very near the close of the dry season and were found bearing 

 embryos in various stages of development and in some instances 

 well advanced sporogonia as shown in Fig. i. By the first of 

 Januar}'^ the spores and elaters had matured and some capsules 

 had already dehisced. 



Not having observed these plants at the time of fertilization 

 it cannot be definitely said just when the antheridia and arche- 

 gonia matured. However, the approximate date may be ascer- 

 tained by observing the rate of development of the sporogonium 

 and of the ripening of the spores. In 1904 the first rain of 



'Abrams, 1S99: Structure and Development of Cryptomitrium tenerum. 

 Botanical Gazette, Vol. 28, pp. 110-121. 



