The structure & development of the mosses and ferns (Archegoniatae) . developed stoma SCCm tO liaVC bcCU obscrVCd infrom the epidermis of the sporogonium of ,4. ^ , . ,-^, ~ . ^ . i<evis, X250. A. IcBvts. ihe spores 01 A. fusi- forinis are protected by a perfectlyopaque black exospore, which is covered with small spines ortubercles. These spores will not germinate readily when fresh,but after resting for a few months grow freely. As in othersimilar spores, the exospore is ruptured along the three ridgesupon the ventral side { that with which it was in contact withthe other spores of the
The structure & development of the mosses and ferns (Archegoniatae) . developed stoma SCCm tO liaVC bcCU obscrVCd infrom the epidermis of the sporogonium of ,4. ^ , . ,-^, ~ . ^ . i<evis, X250. A. IcBvts. ihe spores 01 A. fusi- forinis are protected by a perfectlyopaque black exospore, which is covered with small spines ortubercles. These spores will not germinate readily when fresh,but after resting for a few months grow freely. As in othersimilar spores, the exospore is ruptured along the three ridgesupon the ventral side { that with which it was in contact withthe other spores of the tetrad), and through this cleft the endo-spore protrudes as a papilla which sometimes grows into a verylong germ tube, or more commonly divides before it reaches agreat length. Into this tube passes the single chromatophorewhich, during the early period of germination, has resumed itsgreen colour, and with it the oil drops and other contents ofthe spore. A good deal of variation was observed here in the ^ Hofmeister (l) ; Gronland (i) ; Leitgeb (7), vol. v. p. THE ANTHOCEROTE^ 137 first divisions, as is the case in A. IcBvis. The first divisionwall is, in most cases at least, transverse, and is usually followedby a second similar one, before any longitudinal walls in the end cell two intersecting walls and the formationof four terminal quadrant cells are often seen (Fig. 66, D), asin other Hepaticae. Variations from this type are often metwith, and some of these are shown in the figures. Verycommonly a second cell is cut off by an oblique wall from thegerm tube subsequent to the first transverse wall, but this doesnot, at least in the early stages, develop into a root-hair, the
Size: 1451px × 1722px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
