362 THE "pro-embryo" of chara. 



I cannot iDroceed, therefore, as Bennett does, to unite the 

 Characeic with the ^hiscmea:^' I regard them as forming an inde- 

 pendent group intermediate between the Carposporea and the 

 2Imcinc(c. Tliis is really to say that they link the Thallophytes 

 to the Cormophytes, and this I believe to be actually the case. In 

 the structure of their vegetative and reproductive organs they 

 resemble the cormoid Thallophytes on the one hand and the 

 thalloid Cormophytes on the other. 



Caruel proposes to j)lace the CharacecB (his Schistogams) 

 between the Vascular Cryptogams (his Prothallogams) and the 

 Phanerogams. He rejects, as I do, the supposed homology of the 

 " pro-embryo" of Chara with the protonema of a Moss, and partly 

 on this ground and partly on the ground that in Mosses the 

 '' neutral form "' (sporophore ?) is definite in its evolution, whereas 

 in Chara it is indefinite, he separates widely the Characea from the 

 MuscinccBm spite of many obvious resemblances. Of these reasons 

 the former is quite insufficient, as a consideration of the foregoing 

 paragraphs of this paper will shew. As to the latter, the observa- 

 :^ions of Pringsheim and of Stahl, to which reference has been 

 made above, shew that the ''neutral form" of a Moss is not 

 necessarily definite in its evolution. I am unable to ascertain 

 exactly from his paper or from his book what Prof. Caruel con- 

 siders to be the " neutral form " of Chara, but if it is either the 

 oospore or the " pro-embryo," these sm-ely are definite in their 

 evolution. He goes on to separate the Characea; from the Prothal- 

 logams on account of the absence from the former of "anything 

 like the sexual prothallus so peculiar to the Prothallogams," and 

 also on account of " the com^Dlex organisation of the antherocj^st 

 (globule) compared to the simj)ler antheridium, and o f the 

 oogemma (nucule) compared to the archegonium, and of the 

 different origin of both, which m Characecc proceed du'ectly from 

 the neutral form and not from spores produced by it." Are we then 

 to cease to regard the sexual C'Aam-plant as corresponding to the 

 prothallus of a Fern, and are we to consider the sexual organs 

 which it bears as a separate sexual generation ? Surely this is a 

 view which has no foundation in true morphology. Can there be 

 any reason for regarding the archegonia and antheridia of Chara as 

 constituting a generation distinct from the plant which bears them, 

 whilst no such distinction is made in the case of the prothallus of 

 a Fern ? The feature of the Characea to which importance is 

 attached as indicating a relationship with the Phanerogams is the 

 " marked resemblance of structure, coupled with the same origin, 

 between the oogemma of the one and the gemmule (misnamed 

 ovule) of the other," and further, " the similarity of origin in the 

 male forms of both the groups, equally proceeding from bodies 

 which are modifications of leaves." Even if we admit, as Caruel 

 does, that Celakovsky + has satisfactorily proved that the central- 



* This has been done also by Trevisan. (Conspectus ordinum Prothallo- 

 phytorum, in 'Bull. Soc. Bot. Belg.', Ib77.) He unites the Bryojphyta and 

 rhiicophyta {Characea) into oue group which he calls Anthogamce. 

 f ' Flora," 1878, p. 49. 



