DESCRIPTIONS OF THE SPECIES 
34i 
terete or somewhat flattened, nine to eighteen inches long, 
one line diameter, hardly narrowed to the rounded point, 
flaccid, rising to the surface of the water, then floating and 
more flattened. No stomata on the submerged parts; floating 
parts dark green and grass-like. Veins one central and one 
marginal on each side throughout. Membranous leaf-base 
dilated, and its margins enclosing and half covering the 
sporangium on its upper surface. Sporangia usually produced 
in the base of every leaf, one-third inch long, one-sixth inch 
wide, membranous, the outer containing a few macrospores, 
the inner containing numerous microspores. Macrospores 
white, hard, three-ridged, tubercular; microspores very minute. 
Floating in ponds around East London, and in the Victoria 
Park, East London. First found by Mr W. H. Wormald, 
Dec. 1893. 
Abundant in these ponds, 1902 (T. R. Sim, 1567). 
Described and illustrated by us in Trans. S. A. Phil. Soc., 
Vol. 16, Pt 3 (Aug, 1906), which illustration is reproduced 
here. 
COHORT III. SPHENOPHYLLALES. 
ORDER VIII. PSILOTACEAE. 
Genus 60. PsiLOTUM Swartz. 
Epiphytal, rigid, almost leafless plants, with much-twisted 
stems, repeatedly branched dichotomously, and bearing the 
sporangiophores in the axils of the few small scattered leaves. 
Sporangiophore three-lobed, consisting of three sporangia 
united together, without indusium. Included in Lycopo- 
diaceae in our first edition on account of the uniform sporangia 
and spores, but now separated as having a sporangiophore of 
three united sporangia, each cell splitting down its central face 
to discharge the oblong spores from which the prothallia are 
produced. Roots like those of Lycopodium, and from near 
the base only. 
The genus consists of one or two species of tropical and 
sub-tropical plants. 
