246 
F. E. Fritsch. 
k 
Yamanouchi, 1 with the result that the features of reduction corres¬ 
pond closely with those obtaining among the higher plants, includes 
the erect sexual C'w/Zma-plant and the prostrate asexual Aglaozonia- 
plant, normally following one another in definite alternation. 
Parthenogenesis is a rather frequent phenomenon, the partheno- 
spores, however, giving rise to more or less distinct Aglaozonia-stnges. 
But there are numerous other important abnormalities. Thus, the 
zoospores, whilst often growing into typical Cutleria-tha\\\, occasion- 
ally 3 afford dwarfed thalli or even only simple, or more rarely branched, 
threads; these abnormal individuals (Fig. 2, c) sometimes produce 
gametangia on the erect system, hut almost invariably grow out 
into AglaozoniaAWio. discs at their base. Oltmanns 3 interprets such 
stages as instances of a secondary formation of Aglaozonias by 
budding from the Cutlevia- plant, but the writer would like to place 
a totally different interpretation upon them. 
It seems likely that the ancestor of these forms had a thallus 
differentiated into the usual prostrate base and erect portion (cf. 
p. 14), in fact in the normal Aglaozonia- stage this is quite apparent, 
the base being represented by the Aglaozonia-d'xso. and the upright 
system by the small erect column which invariably arises in the 
germination of the Aglaozonia-yYant (Fig. 2, b). Young Cutleria- 
plants also seem to display some indications of a creeping basal 
system. It may be suggested, therefore, that the ancestor of 
Cutleria had a thallus bearing asexual organs near the base and 
sexual organs on the upright system, as we find it in Myrionetna, 
etc., among the present day Ectocarpales (p. 14 ). With the 
development of these organs at different periods, they became 
segregated on distinct individuals, the asexual ones practically 
losing the upright system and the sexual ones the prostrate portion. 
The erect column of the Aglaozonia- stage would thus he a relict of 
the original erect system, whilst the abnormal stages above described 
would merely be a return to the ancestral condition. Sauvageau 4 
has described stages which appear as transitions between young 
Cutleria- plants and the column of the Aglaozonia- stage, and these 
are quite in accord with the above hypothesis. All the evidence 
seems to point to the conclusion that the two generations of Cutleria 
1 cf. Yamanouchi, in Bot. Gaz., XLVIII, 1909, pp. 380—387. 
2 Church, “ Polymorphy of Cutleria multifida,” Ann. of Bot., XII, 1898, p.75 ; 
Kuckuck, in Wiss. Meeresunters. Abt. Heligoland, III, 1900, pp. 01—79; cf. also 
Oltmanns, loc. cit., p. 403. 
3 loc. cit., p. 403. 
* P 
4 Ann. sci. nat., bot., 8 ser., X, 1899, p. 265. 
