118 “THE JOURNAL OF BOTANY 
pores on the outer surface of br. 1. . — and 
almost exclusively in the upper angles of the cells; on 
the inner surface wanting, or in n the: angles of ‘the cells of 
the apical half of the leaf noma rarely almost to the leaf- 
base ; chlor. cells in raoeey rectangular-trapezoid, free on 
both surfaces stem cortex ge pitérelly clearly differentiated 
from the re a . xvi. S. cuspidatum Russ. & Warnst. 
14. St. 1. sane! wilneblias finpalate, towards the apex usually 
with fibrils; border of br. 1. up to six cells wide; pores 
on the outer surface of br. 1. very numerous; in the apical 
half of the leaf, in a single row in the centre of the cell- 
wall, and here at times becoming converted into large 
membrane-gaps ; in the lower part of the leaf oui 
in two rows near the commissures, either with a 
ring or non-bordered, but with a sharp contour, 6- Ty 
diameter; chlor. cells and stem cortex as in S. cuspi aie, 
which it approaches most perm ar n habit. 
. S. Dusenii Russ. & Warnst. 
14. St. 1. large, triangular- eipiite. i the apex usually 
with rudimentary, or in part completely developed, fibrils; 
border of br. 1. narrow, 3-4 cells wide; pores on the outer 
wall; towards rn leaf-apex strongly ringed and resembling 
strings of pearl oe times ela by pseudo-pores ; 
r. cells in section triangular, on the leaf inner surface 
completely aaisloasil by the hy ts cells which are united 
toge or some distance; stem cortex not clearly 
differentiated from the  ugeeaae he! cylinder, and thus 
apparently absent . . i. S. annulatum Lindb. fil. 
14. St. 1. rather large, clanealar: nga ; always without 
ae on we outer surface e br. 1. with extremely 
mall, about 2 5 in aes, ill- ea pores which only 
mara visible by intense staining of the cell-wall. These 
pores are sometimes found only in the basal part of the 
leaf, and especially towards the margins, sometimes (but 
rarely) they are in ie rows os the cell-walls throughout 
the entire outer surfac e inner surface of the br. 1. 
pores are usually anbeely. sae very rarely both leaf- 
surfaces are almost without any eles lor. cells in 
section asin S. annulatum . . . xix. S. obtusum Warnst. 
14. St. 1. almost always small, equilateral- camels to short- 
br. 1. in the middle and basal part of the leaf, large, and 
situated in the upper angles of the cells near the margins 
of the leaf; or there are here nso = on the eer of 
each cell. The pores on the o surface in the upper 
angles of the cells are seas ge heer laraodiatale: oa 
