GROWTH AKD SEXUAL GENESIS. 431 



further factor which here complicates the result — the ago al 

 which sexual genesis commences. The smaller Phsenogama 

 are mostly either annuals, or perennials that die down 

 annually ; and seeding as they do annually before their 

 deaths, or the deaths of their reproductive parts, it results 

 that in the course of a year, each gives origin to a multitude 

 of potential plants, of which every one may the next year, if 

 preserved, give origin to an equal multitude. Supposing but 

 a hundred offspring to be produced the first year, ten 

 thousand may be produced in the second year, a million in 

 the third, a hundred millions in the fourth. Meanwhile, 

 what has been the possible multiplication of a large Phae- 

 nogam? While its small congener has been seeding and 

 dying, and leaving multitudinous progeny to seed and die, it 

 has simply been growing; and may so continue to grow for 

 ten or a dozen years without bearing fruit. Before a Cocoa- 

 nut tree has ripened its first cluster of nuts, the descendants 

 of a wheat plant, supposing them all to survive and multiply, 

 will have become numerous enough to occupy the whole 

 surface of the Earth. So that though, when it begins to 

 bear, a tree may annually shed as many seeds as a herb, yet 

 in consequence of this delay in bearing, its fertility is incom- 

 parably less ; and its relatively-small fertility becomes still 

 further reduced where, as in Lodoicea Sechellarum, the seeds 

 take two years from the date of fertilization to the date of 

 gei'mination. 



§ 340. Some observers state that in certain Protozoa there 

 occurs a process of conjugation akin to that which the 

 Protopliyta exhibit — a coalescence of the substance of two 

 individuals to form a germ-mass. This has been alleged 

 more ecpecially of Actinophrys. The statement is question- 

 able ; but if proved true, then of the minute forms that 

 appear to be more animal than vegetal in their characters, 

 some have a mode of sexual multiplication by which the 

 parents are sacrificed bodily in the production of a new 

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