1899] DEVELOPMENT OF HOLDFASTS OF FLORIDEZ 249 
_ developing under natural conditions, accurately describes those 
grown in the laboratory. A somewhat spherical mass composed 
_ ofsixteen cells results from the segmentation of the spore, then 
the first indication of a permanent holdfast appears as a slight 
projection of each of the four basal cells. The primary root- 
cells, dividing at right angles to their longest axis, form two- 
celled filaments, which branch monopodially and give rise to a 
j broad spreading. holdfast. In section the mature holdfast 
_ appears parenchymatous (P/. XX7, figs. 77, 18), but it is often 
_ possible to distinguish the component filaments (P2. XXY, fig. 20). 
' Exceptional plantlets produce one instead ot four primary root- 
j cells, but the later stages conform to the type (Pl. XX, fig. 79). 
__ Inall cases the cells of the holdfast are paler than those of the 
; frond, and the chromatophores of young specimens are in close 
_ eontact with the walls. . 
: From the foregoing it will be seen that Rhabdonia, Lomen- 
‘ “ra, and Champia agree (az) in passing through a segmenta- 
ee stage, resulting in a somewhat spherical mass of cells, (4) 
im the elongation of four basal cells, and (c) in the subsequent 
_ tevelopment of four primary rhizoids, which branch repeatedly 
and finally form a large discoid holdfast, composed of pseudo- 
‘ parenchymatous tissue. 
: "marked contrast are several members of the Rhodome 
' - The spores of Chondria tenuissima (Good. et Wood.) C. 
FE ae ose Chondria dasyphila Ag. germinate very readily. The 
« : em of the spores and the history of the development 
i las '20ids are alike in the two species. The spores, which 
eo and have coarsely granular contents, quickly and 
Sie attach themselves to the substratum, doubtless by means 
‘i hin and uniform layer of mucilage, though no secretion 
fin the cell-wall is perce tible (PLXXT, fig. 23). They 
a Son divide into t : lightly con- 
ee wo unequal cells separated by a slightly 
2d the parallel to the first follow (Pl. XXV/, FE. ue 
Primary oo cell of the resulting filament elongates into the 
oid (PL. XX7, figs. 25, 27). Sometimes the basal cell 
® branch dichotomously ; but, as the branches do not 
