129 
NOTES ON THE HISTOLOGY OF POLYSIPHONIA 
FASTIGIATA (Rotu.) Grey. 
By R. J. Harvey Gisson, M.A., F.L.S., F.R.S.E. 
(Lecturer on Botany in University College, Liverpool.) 
[Puate 304.) 
escape of the tetraspores ; (c) the pericentral intercellular spaces ; 
(d) pe mode of union of the epiphyte to the ‘“‘ host" plant. 
The continuity of pr septa between ‘ie cells of the frond.— 
Wrighi* describes the protoplasmic contents both of the central 
and pericentral cells as being, in the young condition, in complete 
esc aan but states that, as the cell becomes mature, the 
since eked place,” the canal-like pits in the enitea and pericentral 
cell-walls are not oeenpied by protoplasm, but by granular second 
deposits. Schmitz} as , on the contrary, that the protoplasmic 
int he is erste tain the life of the cells. Mass ee § says 
-* 
maintained. ‘After the apenas ge r sent a aii: size, 
of which the pore sac or p attached. 
The plate is perforated by. Geert hole through which slender 
threads of protoplasm pass. 
In a paper by Wright, ‘On the Cell-structure of Grifithsia 
setacea Ellis, and on the Development of its Antheridia and Tetra- 
spores,”|| the author describes the ‘‘plugs”’ in that species as, in 
older cells, composed of two plates, which may be separated by the 
action of reagents 
That the protoplasmic contents of two central, of central and peri- 
central, or of two pericentral cells, communicate in the young state, 
there can be no doubt. That the continuity of protoplasm is main- 
tained in older conditions is, [think, not the case. In the first place, 
* « On the so-called Bipot, and ot the ana, of the Tetrasporesin ~ 
7. Acad. XX 
Polysiphonia,” Trans. 
+ “On the Minute eile and stots ‘a ee of Ballia callitricha,” 
Trans. hia. Soc. (Bot.), vol. i. pt. 4, P- 
ee. oe iiber d. Fruchtbild. d. Poa, ” Akad. d. Wissensch. z. Berlin, — 
g “On oe een and Growth of Cells in the Genus Polysiphonia,” 
Jour. fey Mier. Soe 
|| Trans. Roy. aS ae xxvi. p. 491. é 
JOURNAL OF cae. —Vou. 29. [May, 1891.]} K 
oe 
