320 



ABNORMALITIES OF THE LIFE-CYCLE 



[CH. 



their legitimate value these departures from that simple cycle which is 

 regarded as normal. (See Fig. 28, p. 21.) 



It will suffice here to mention the vegetative increase, whether of the 

 sporophyte or of the gametophyte, by buds or gemmae, for examples of both 

 of them have already been described (Figs. 66^ P- 72; 271, p. 281). Such 

 ' sporophytic or gametophytic budding results merely in a repetition of the same 

 phase of the life-cycle as that from which they arose, and the budding may be 

 repeated over and over again. A much greater importance attaches to those 

 modifications which involve in one form or another the elimination of essential 



Fig. 296. Apospory. A = '&ox2\ z.T^o'iy^oxy ol Athyriitm Fiiix-foeniiiia,\'xx. clanssinia,']oxi&?,. Part of 

 a pinnule with veins [vb), and a sorus. In the latter, in place of the sporangia prothalli are formed 

 (p7-ih), with antheridia (anth), and archegonia [arch). ( X40.) j5 = apical ix^os^ory oi Pofystickum 

 angtdare, \2.x. pulcherrimwn, Padley. A prothallus arises at the tip of a pinnule, as a direct con- 

 tinuation of it. ^/= marginal glands; r= the cushion. ( x 20.) Continued o)i p. ii\. 



events in the life-cycle. These may be ranked under two heads : Apospory, 

 by which name are designated those cases where spore-production is omitted 

 from the life-cycle, and a direct transition is effected, by continuous vegeta- 

 tive development, from the sporophyte to the gametophyte ; and Apogaiuy, 

 or to use the later and more comprehensive term Aponiixis, which connotes 

 the omission in one form or another of the act of syngamy, whereby a 

 vegetative transition is effected from the gametophyte to the sporophyte. 



The first intimation of a departure from the regular cycle of events in 

 Ferns was made by Farlow (1874), who noted the vegetative production of 



