248 BOTANICAL GAZETTE [ocToses 
In about thirteen days differentiation begins. Four basal cells 
elongate to form the primary root-cells, the position of which 
bears no definite relation to the direction of the supply of 
light (71. XXT, figs. 7, 8). Occasionally only one or two pri- 
mary rhizoids are thus formed (Pl. XXI, figs. 9, 10, 1). 
Unfortunately, the plantlets died at this stage, and only by 
analogy could the subsequent history of the holdfasts be 
determined. However, the close resemblance between the pri- 
mary root-cells and, mature holdfasts of Rhabdonia and of the 
two species to be considered next justifies the assumption that 
the intermediate stages closely agree. It is interesting to note 
that, according to Osterhout (7), the earliest divisions in the 
tetraspores which give rise to proliferations do not succeed one 
another in the definite order just described, but the spores divide 
“by means of oblique walls which do not occur in regular suc 
cession.” 
Very similar to that of Rhabdonia is the early history of 
Lomentaria uncinata Menegh. and of Champia parvula Harty. The 
carpospores of Lomentaria, after secreting a wall, attach them 
selves to the substratum by a very thin mucilaginous secretion 
(Pl. XXT, fig. 12), which sometimes persists after the first 
thizoids have been formed (Pl. XXV, fig. 15). The — 
tion proceeds rapidly, but primary root-cells do not arise pes 
a later date than in Rhabdonia (Pl. XAT, figs. 13: 14). 
four basal root-cells, dividing by horizontal walls, ; 
short, closely-appressed filaments, which soon branch pseu af 
dichotomously (Pl. XX7, figs. 15, 76) and forma ae 
Strémfelt (8) regards the branching of the rhizoidal per é 
dichotomous and says that the increase in circumference : c 
mature holdfast is due almost entirely to marginal growth. pie? 
tative reproduction may take place not only by po 
separation of the various upright branches, which sprin 
tiously from the surface of the holdfast (P/. XX, fig: 2? 
oy means of stolons, which are sent out in 
and form secondary holdfasts (PZ. XXV, fig: 21) 548 parc 
Davis’s account (4) of the plantlets of Champa 
become — 
discoid holdfast. 
various directions 
