HISTORICAL RETIEW OF THE FLORIDE^ 331 



II. Caeposporophtte, bearing reduced unilocular monosporano-ia, 



dispersing diploid carpospores. The latter germinates to a' 



III. Tetrasporophyte, as a free autotrophic individual, also pro- 



ducing unilocular sporangia, but these giving rise to one 

 tetrad of 4 spores, associated with meiotic mechanism and 

 dispersing haploid tetraspores. 



Or, considering these general phenomena in further detail: — 



I. The sexual plants (gametophytes) have long attained to the 

 extreme limit of sexual economy and efficiency as expressed by ferti- 

 lization in situ ; in the progression to which the flagellated zoid 

 (antherozoid) has been w^hoUy lost. The contents of the antheridium, 

 reduced to the limiting expression of an immobile * spermatium ' 

 discharged in its endochiton, fuse (spermatogamy) with a specialized 

 hair-attachment process (trichogyne) of the oogonium (carpogonium). 

 Preceding states of heterogamic progression ai-e superseded by post- 

 sexual nutrition, and the gametes are expressed as mere nuclei (a con- 

 dition otherwise attained by the highest Angiosperms only by very 

 devious routes). The possibility of the initiation of such post-sexual 

 nutrition of the zygote is now seen to depend on the mechanism of 

 the primary pit-connection left open at the base of the young carpo- 

 gonium, and hence follows legitimately as an opportunist utilization 

 of a factor of ancestral organization. 



II. The parasitic zygote thus ' germinating ' in situ, and nourished 

 by the parent, is necessarily asexual and devoted to the production 

 of asexual s^Dores, since a sexual plant parasitic on a jDarental sexual 

 organism would be in bad case; but such plants in catena, with 

 fertilization in situ, would be an impossibility, as destroying the 

 whole idea of the retention of the sexual process. Whether such .t 

 second generation is diploid or haploid is purely immaterial (the 

 former is as a matter of fact the rule, since there was no inducement 

 afforded for meiosis at ' germination '), but they must produce freelv- 

 shed spores. On the other hand, the extreme decadence of the attached 

 parasitic generation, recognized as a mere tuft of gonimoblasts at the 

 best, is expressed also in the deterioration of the unilocular sporan- 

 gium (which should have been a tetrasporangium at one time, in the 

 manner of Dictyotd) to the state of a monosporangium, in which the 

 uninucleated contents are discharged in endochiton as carpospores; 

 meiosis being omitted, or alternatively described as ' delayed.' Hence 

 the second parasitic individual or generation may be conveniently 

 termed the carposporophyte, prevailingh^, though by no means neces- 

 sarily, diploid in its nuclear organization. 



III. The free carpospores, being dispei-sed, take the small chances 

 of immediate germination on attachment to any available substratum, 

 and grow to a free autotrophic soma, in all respects like the first 

 autotrophic individual ; vegetating in exactly the same way, and 

 carrying on the nuclear organization of the parent carposporophyte, 

 to produce again unilocular sporangia, this time with fully nourished 

 meiotic mechanism and production of the limiting tetrad of four 

 tetraspores. The latter are in turn freely discharged to the external 

 medium, as haploid immobile units. The third individual is tlius 



