DESCRIPTIONS OF THE SPECIES 
33i 
two-valved, arranged in the axils of bracts in spikes terminal 
on the branches. The smaller kind of sporangia, which 
contain numerous small spores, occupy the upper part of 
the spike, and the larger kind occupy the lower part, and 
contain several large spores, which on development produce a 
minute prothallium, on which fertilisation takes place. There 
are very many species, and the genus is represented in all 
warmer countries. The habit of growth in Isoetes is altogether 
different. 
Synopsis of the species : 
§ Leaves set all round the stem, and all of one kind. 
207. 6'. pumila. Annual, sub-erect, leaves not awned. 
208. S.rupestris . Perennial, procumbent, leaves awned. 
§§ Leaves of two kinds, one line of larger spreading leaves along both 
sides of the decumbent stem, and two lines of smaller ascending 
leaves on the upper surface. Bracts uniform with the leaves, but 
smaller. Perennials of firm texture. 
209. S. depressa. Stem not jointed, two to three inches long, 
slightly branched, procumbent. 
210. S. Kraussiana . Stem jointed, six to twelve inches long, 
much branched, prostrate. 
21 1. S.imbricata. Stems erect, tufted. 
§§§ Leaves as in the previous section. Annuals of thin texture. 
212. S. integerrima. Leaves not ciliated at all. 
213. S. tectissima. Leaves half line long, strongly ciliated on 
the upper side at the base. Smaller leaves cuspidate. Spike 
half line diameter. 
214. S. Mackenii. Leaves one line long, shortly ciliated on the 
upper side at the base ; smaller leaves not cuspidate. Spike 
one line diameter. 
215. S. Cooperi. Leaves one line long, strongly ciliated on the 
upper side at the base ; smaller leaves cuspidate. Spikes 
quarter inch long, one line diameter. 
§§§§ Leaves as in section 2 ; spikes resupinate (i.e. the smaller bracts 
in the same plane as the larger leaves, and vice versa). 
216. S. molliceps. Stems erect, tufted. 
The third section is altogether unknown to me, and the 
descriptions given are from Baker’s Fern Allies. 
