In this class the plumule, or bud, is in germination developed from a sheath-like cavity on one side of the embryo.

Although among the Monocotyledonous orders we do not meet with so many instances of adaptation to insects as is the case in the Dicotyledons; none are more curious or interesting than those afforded by the Orchidaceae.

Alismaceae

Alisma Plantago has rather small, pale, rose-coloured flowers, forming a loose pyramidal panicle one to three feet high. The flowers secrete honey from twelve glands, situated on each side of the projecting bases of the stamens. These are six in number, and the pollen-covered side of the anthers is, according to H. Muller, turned outwards. Under these circumstances, insects are more likely to fertilise the flower with pollen obtained from another blossom than with its own.

In Butomus, on the contrary, the flowers are on stalks, and form a large flat umbel. They are proterandrous; while Triglochin, according to Axell, is proterogynous.

Hydrocharideae

This order contains three British genera; Elodea, Hydrocharis, and Stratiotes.

Elodea canadensis (Anacharis Alsinastruiri) is a common American weed, which first appeared in our country in 1847, and has since spread with great rapidity. It is dicecious, and it is remarkable that it has not as yet been known to produce male flowers in this country; they are, moreover, rare in America. The female flowers are small, with a long, threadlike, perianth-tube, containing a style which terminates in three stigmas.

Stratiotes aloides is also dioecious. The male flowers are contained several together in a spathe, stalked, and have twelve or more stamens. The female flowers are solitary and sessile. Both sexes secrete honey.