6 ANTONY GEPP AND ETHEL S. GEPP. 
calibus oblongis parenchymaticis in circa 6-7 series dispositis; medullaribus elongatis 
angustis strictis 9-10 seriatis tubulos perpaucos subinfundibuliformes vagina e cellulis 
parvulis composita vestitos foventibus. Caetera desunt (fig. 10). 
South Orkneys, Scotia Bay, near surface ; April, 1904, leg. R. N. Rudmose Brown. 
A section of the lamina of this plant was figured in the Journal of Botany (Joe. 
cit.) as representing that of LZ. grandifolia. We had at the time no doubt that the 
‘Scotia’ specimens which, though fragmentary, presented so striking an external 
likeness to the type, were identical with it; for such differences of structure as were 
apparent seemed to be due to a different method of preservation. The ‘ Scotia’ 
specimens were preserved in spirit, and exhibited a simpler and clearer cell-structure 
than the ‘ Discovery ’ material, which was preserved in formalin or merely dried. But, 
after having made a more careful comparison of their microscopic structure, we are 
convinced that the ‘Scotia’ plant must be separated off as a proper species, though the 
material is insufficient to enable us to describe its complete habit. 
As regards the structure of the lamina, the cortex is monostromatic and composed 
of quadratic thin-walled cells with granular contents (not rotundate and densely 
obseured, as erroneously figured in the Journal of Botany, loc. cit.). The subcortical 
tissue consists of about six layers of larger cells, rounded or oblong, lengthened parallel 
to the axis of the frond; and the medulla is composed of some nine to ten rows of 
narrow elongated cells, thick-walled, with a few ensheathed trumpet-hyphe scattered 
among them. The medullary cells are sometimes filled with a pale brown mucilage, 
and their limits are then barely distinguishable. 
In the stipes the medulla is the main tissue, and consists of a dense pale-brown 
mass of hyphe, chiefly longitudinal (fig. 10) and straight, but here and there mingled 
with interwoven hyphze. Scattered in the medulla are a very few trumpet-hyphe, 
some with and some without a sheath of very small cells. The medulla externally 
changes into a pluristromatic subcortex of large round and oblong cells which, passing 
outwards in radial rows and subdividing, gradually changes to a cortex of three to four 
rows of small quadrate cells, bounded by distinct cuticle. 
The structure of the holdfasts rather resembles that of the stipes, but the strata 
are less definitely marked ; there is a dense medullary mass of hyphze which towards 
the periphery change into lax, larger, thm-walled subcortical cells, and these in their 
turn becoming smaller and smaller, pass into a cortex of small dense-coloured quadrate 
cells. There are no trumpet-hyphe in the medulla of the holdfasts. 
The most obvious difference between LZ. stimulans and L. grandifolia is found in the 
medulla of the lamina. This in the former plant isa very pale-brown tissue of elongated 
cells with very few ensheathed trumpet-hyphe. In L. grandifolia the medulla is 
colourless and composed of hyph mostly longitudinal, and laxly juxtaposed and 
separated from one another by one to two times their diameter. The ensheathed 
trumpet-hyphze are numerous and obvious, and scattered along an irregular median line. 
L, simulans differs also in having a monostromatic cortex of quadrate cells, 
