603 
pronouncedly lateral, the branches arising at a long distance below the apex. All 
the shoots taper upwards. 
As to the structure of the tip of the frond, the authors do not agree. 
Kırrıan (1914) described the germination of the carpospores and found that the 
spore divides by vertical walls, forming an orbicular disc increasing by continued 
anticlinal and periclinal cell-divisions. The central part of the disc becomes vaulted, 
and one of the central cells develops more vigorously than the others; it becomes 
the initial cell of the primary upright frond issuing from the disc. The young frond 
has then a single triangular initial cell at 
the top (l. c. figs. 5—10); but KırLıan 
thought that this cell was later divided into 
a greater number of initial cells, and Ssö- 
STEDT (1926) is of the same opinion. KyLIN 
has, however, recently shown (1930, p. 55) 
that the tips of the older fronds have the 
same structure as that described by KırLLıan 
in the germling, and the species can thus 
be referred to the type with a central axis 
(“Centralfaden-Typus”), although an axial 
cell-row is not present. 
The structure of the frond has been 
finely illustrated by THurET (1878) and 
described by Ss6stEpT and Kyrın (1930). 
The frond is early differentiated into a thin 
cortex composed of two or three layers of Fig. 605. 
cells and a large medullary tissue built up  Gracitaria confervoides. M Transverse serhomoffrenn 
of large, round, isodiametrical cells not With a hair. B and C, basal portions of hairs. D, 
cortical cells. E, medullar cells showing secondary 
lengthened in a longitudinal direction. These pits seen from the face. A—D 560 : 1. E 420: 1. 
cells are connected by numerous pits, partly 
secondary, and are without any rhizoids (fig. 605 E). The young cortical cells con- 
tain one nucleus while the older and inner cells may contain a greater number. 
Each cortical cell contains several chromatophores which are long, linear, ribbon- 
shaped, bent and sometimes branched; they are most easily seen in the inner cortical 
and the outer medullar cells (fig. 605 D). 
The young parts of the shoots bear numerous hairs (fig. 605). They were first 
briefly mentioned by me (1911, pp. 206, 208). Later PrirLırs observed the hair- 
producing cells but misinterpreted them as carpogonia (1925), whereafter SJÖSTEDT 
(1926) gave a description of the development and structure of the hairs (in Gr. 
compressa). They arise early (in Gr. confervoides) from primary cortical cells which 
remain undivided and therefore by continued growth become larger than the 
surrounding dividing cortical cells (fig. 605 A). The hair-bearing cell is con- 
nected with the hair by a narrow pit the transverse wall of which is situated 
"== 
11 
