XI.— THE FROG-BIT. 
Hydrocharis Morsus-rana Linne. 
W E may take this opportunity of explaining, what we have hitherto neglected 
to mention, that the practice of botanists is, while writing the first or generic 
name of all plants with an initial capital whenever it is used, or abbreviating it to a 
single initial letter when several species of the same genus are mentioned in succession, 
to begin the second of the two names that every species bears — the specific name — 
with a small initial. To this latter part of the rule, however, there are exceptions, 
the specific name being written with a capital when it is the name of a person or 
when, as in Hydrocharis Morsus-ran<e , it is an old generic name. 
This genus Hydrocharis gives its name to a Family, the Hydrocharilace <e, the 
position of which in the classification we here adopt is the main distinction between 
the Order Helobie<e and the Cohort Potamales of that of Bentham and Hooker. By 
those authorities the Family was separated from those with which it is here associated, 
on account of its inferior ovary ; but, as in many other cases, this character is not 
nowadays allowed to outweigh other indications of affinity. The Family is not a 
large one, comprising as it does some fourteen genera and less than sixty known 
species ; but, like so many other groups of aquatic plants, it is widely distributed 
in almost all climates, and it includes several of the few genera of flowering plants 
that live in sea-water. They are all herbaceous, mostly perennial, and either 
submerged, with ribbon-like leaves, or floating. Their leaves vary considerably, being 
sometimes cauline, whorled, or rising above the water, sometimes toothed at the 
margin, and sometimes reduced to a flattened petiole or phyllode ; but they have 
“ squamulae intravagi nales ” and produce stolons from axillary buds, of which there 
are often more than one in an axil. Like many other aquatics, they multiply largely 
by such purely vegetative methods as these stolons, either not flowering freely or 
not producing fertile seed. Their flowers are mostly dioecious, though conspicuous, 
and are enclosed, in the bud stage, in a sheath or spathe , a structure common to 
many groups of Monocotyledons, but not a safe indication of affinity in the absence 
of other characters common to the presumed allies. The perianth, consisting of six 
leaves in two whorls, of which the outer is calyx-like and the inner petaloid and more 
conspicuous, resembles that of the Alismace<e ; but differs markedly in being epigynous 
or superior. The stamens are three to fifteen in number, in alternating whorls or 
three each, some of them being sometimes aborted and all of them often slightly 
united at their bases, as in some of the allied types that we have just described, but 
attached to the segments of the perianth ( epigynous and epiphyllous ). The carpels are, 
perhaps, never less than two, often six, and sometimes as many as fifteen, forming a 
one- or more-chambered ovary, surmounted by bifurcating stigmas and having parietal 
placentation , i.e. the ovules attached to the outer wall of the ovary. The fruits ripen 
under water, split open irregularly as they decay, so liberating the seeds, which are 
