IV. 



THE ANTHOCEROTES 



143 



centimetres or more in length, and reaches nearly this length 

 before the first spores are ripe and the capsule opens. This it 

 does by splitting at the top into two equal valves between 

 which the dried-up columella protrudes. The split deepens as 

 the younger spores ripen, and may finally extend nearly to the 

 base. It is quite possible, although this point was not investi- 

 gated, that the line of dehiscence 

 corresponds to the primary verti- 

 cal wall in the embryo, as is the 

 case in the Jungermanniacese. 



The germination of the 

 spores^ has hitherto been ob- 

 served only in A. Iwvis. A study 

 of the germination in A. fusi- 

 formis shows a general corre- 

 spondence with the results of 

 other observers, but certain points 

 were brought out that do not 

 seem to have been observed in 

 A. lavis. The spores of A. fusi- 

 formis are protected by a per- 

 fectly opaque black exospore, 

 which is covered with small spines or tubercles. These spores 

 will not germinate readily when fresh, but after resting for a 

 few months grow freely. As in other similar spores, the ex- 

 ospore is ruptured along the three ridges upon the ventral side 

 (i. e., that with which it was in contact with the other spores 

 of the tetrad), and through this cleft the endospore protrudes 

 as a papilla which sometimes grows into a very long germ 

 tube, or more commonly divides before it reaches a great 

 length. Into this tube passes the single chromatophore which, 

 during the early period of germination, has resumed its green 

 colour, and with it the oil drops and other contents of the 

 spore. A good deal of variation was observed here in the 

 first divisions, as is the case in A. Icevis. The first division 

 wall is, in most cases at least, transverse, and is usually followed 

 by a second similar one, before any longitudinal walls appear. 

 Then in the end cell two intersecting walls and the formation 

 of four terminal qiiadrant cells are often seen (Fig. 76, D), as 

 in other Hepaticse. Variations from this type are often met 

 'Hofmeister (i) ; Gronland (i) ; Leitgeb (7), vol. v. p. 29. 



Fig. 75.— a, Young ; B, fully developed 

 stoma from the epidermis of the 

 sporogonium of A. Pearsoni^ X^so. 



