476 Fritsch. — The Structure and Development of 
root-ends of the species investigated, and the protoplasm 
extends down into them, often even into their finest branches. 
Sir W. Thiselton-Dyer was kind enough to let me inspect 
some drawings he had made about thirty years back of young 
plants of an Oedogonium , collected in Ireland ; they exhibited 
attaching - discs and more or less elongated and slightly 
branched rhizoids, and the protoplasm extended in a radiating 
manner into all the branches of the former. 
I append a brief discussion of the literature and figures 
published on the structure of the young plants in Oedogonium : 
Leon de Clerc (’17, p. 4 62) speaks of a collar (‘ collet’) at the 
point of constriction (Fig. 2', e ) without saying exactly what 
it consists of. He figures young plants with rhizoids very like 
those of Oed . cardiacum , and possibly his c collet ’ is the brown 
ring. He further figures 1-3 celled plants, which are attached 
to a filament and show but little indication of a basal disc 
(Figs. 2 and 2'). Figs. 5' and 5" show developing plants of 
Oed, Boscii , including apparently some abnormal forms (cf. 
below). 
Ktitzing (’43, Tab. to 1 , Figs. 4-10) figures young plants of 
Oed. vesicatum attached to a water-plant. These merely 
terminate in a point of attachment, but it seems probable to 
me that there was a small basal disc present, which was over- 
looked. 
Thuret (’50, pp. 226 and 227, PI. 19, Figs. 8 and 9) briefly 
mentions the germination of the zoospores and figures a num- 
ber of young plants, all of which have divided root-ends 
(crampons radiciformes) ; Fig. 9 shows two empty unicellular 
plants with lids. 
Cohn (’54, Tab. 20) figures the liberation and the develop- 
ment of the zoospores in Oed. capillar e (Fig. 16). All the young 
plants have more or less branched rhizoids ; no attaching-disc 
is shown. 
Pringsheim (’54, p. 70, foot-note) describes the development 
of the root in a young plant in the following words : c Die 
Zoosporen der Oedogonien sind nicht nur nicht nackt, sondern 
1 Cf. my Fig. 25 m and 27 k. 
