294 PLANT L/FE. 



tions (^ 314) which are homologous with those known to arise 

 from the fertihzccl egi( and adjacent parts. In all these cases 

 the fructification may be considered the homologue of the 

 sporophyte.of higher plants, for, e\'en though its origin is 

 now purely vegetative, this has come about by reduction from 

 more perfect ancestors. 



397. Apogamy. — In certain of the higlier plants sexual re- 

 production is sometimes replaced by a process of budding, 

 which differs from reproduction by brood buds ("[ 361 ff. ) 

 in giving rise to the other ])hase from that on whii h the bud 

 arises. Some ferns, for exauiple, regularly jjroduce upon the 

 garaetophyte a bud wliich grows into a Sl)oroph^•te, the sex- 

 organs Ijeing tunctionless. This i)rocess is called apogamy. 



398. Polyembryoiiy. — Among the seed-|ilants a budding 

 of the megasporangium, instead of the lertilization of the egg, 

 may produce an embryo. Except that the embryo so pro- 

 duced suspends its growth and becomes a part of a seed, such 

 reproduction is in no way different from that by brood buds 

 (^ 361 ff. ) It is common in the orange, and often results in 

 the formation of more than one embryo in the seed. 



Results of sexual union. 



The immediate residt of the coalescence of a male and a 

 female gamete is the formation of a cell capable of producing 

 a new plant, i.e , a spore. The first step toward this is tlie 

 formation of a wall about the spore. It may then grow at 

 once into a new plant, or it ma\' remain doruiant for a longer 

 or shorter time. 



399. Resting spores. — In the latter case it is called a 

 "resting spore." To jirotecl itself, it thickens its wall, often 

 very greatly. It may then escajjc from llie jiarcnt bv the 

 l)i'eaking of tine o\ary in which it lies, InU more connnonly it 

 remains enclosed until set free by the death of the jiarcnt 



