prælongus, etc., have only submerged leaves, which are more or less oblong.
The species with floating leaves form refuges for many interesting low forms of life, and the microscopist will find them very fruitful in specimens for him.
The name is from the Greek words, potamos, a river, and geiton, a neighbour.
Traveller's Joy (Clematis vitalba).
When rambling, in chalky districts especially, our readers will meet this climbing shrub at every turn, scrambling over all the hedges, flinging its arms out over the way, and clinging persistently to any branch or shoot it touches. It has a variety of names, some of which may be applied at different seasons by persons who think they are speaking of different plants. In the early summer it may be the White Vine, or the Virgin's
Bower; in autumn, when the feathery awns are lengthening on its seed-vessels, it may fitly be called the Old Man's Beard, and when winter has cleared most things away from the hedges,
but left these gleaming feathers in abundance, it may give the Traveller Joy to see them as he passes.
It is a perennial plant, with a tough stem, climbing by means of its leaf-stalks, which curl round any likely support, and become hard as wire. The leaves are opposite and compound, the leaflets usually five, the stalks of these also acting as tendrils. The flower has no corolla, but the four thick sepals are coloured greenish-white to serve instead. The stamens are a crowd round the central cluster of many-bearded styles, which afterwards elongate and become the "old men's beards." The flowers, which are slightly fragrant, may be found from July to September.
The Traveller's Joy is peculiarly English, so far as its distribution in the United Kingdom is concerned. It is found only to the south of Denbigh and Stafford. This, too, is the
