Another species--the Butterfly Orchis (_Habenaria bifolia_)--has (usually) undivided tubers; a stem from six to twelve inches high with two broad leaves near the base, and surrounded below by a few sheathing scales; and a rather loose spike of white or greenish flowers with narrow bracts about as long as the ovaries. The petals and upper sepals are arched, the lateral sepals spreading, the lip narrow and undivided, and the spur about twice as long as the ovary. This flower is not uncommon in moist meadows, where it blooms from June to August. A large variety, with greener flowers, is sometimes known as the Great Butterfly Orchis. A considerable number of summer-flowering grasses are more or less common in fields and meadows. We have not space for the descriptions of these, but introduce illustrations of a few, including the Cock's-foot Grass (_Dactylis glomerata_) which appears on Plate IV. XV BOGS, MARSHES AND WET PLACES--SUMMER The Crowfoot group of the _Ranunculaceæ_ contains two bog-plants popularly known as Spearworts on account of their spear-like leaves. One of these--the Lesser Spearwort (_Ranunculus Flammula_)--is abundant in wet places, especially the edges of muddy pools and ditches, where its buttercup-like flowers may be seen from June to September. It is a slender, smooth plant, with a branched stem, more or less decumbent at the base, from four to twelve inches high. Its leaves are narrow-oval in form, stalked, and either slightly toothed or quite entire; and the yellow flowers are about half an inch in diameter, on long peduncles. The other is the Greater Spearwort (_R. Lingua_), a much larger species, varying from two to four feet in height, and flowering during the same months. It has stout, hollow, erect stems which throw off whorls of root fibres from the lowest joints; and the glossy, yellow flowers vary from one to one and a half inches in diameter. This species is not nearly so common as the other, but occurs more or less in most parts of Britain. Taking next the cruciferous plants (_Cruciferæ_), we have first to note a few species of the _Nasturtium_ genus, including the Water-cress and the Yellow-cress. These are all smooth plants, with small yellow or white flowers. They may be distinguished from other crucifers by their loose calyx; simple, rounded stigma on a very short style; and their oblong or narrow pods with the seeds arranged in two rows on each side of the membranous partition. The species with which we are at present concerned are:--