Sweet Gale Family (Myricaceae)
The sweet gale or bayberry family (Myricaceae) is made up of about 50 species of shrubs and trees. Minor economic uses of some species involve the extraction of a fragrant wax from their fruits and cultivation as ornamental shrubs.
The foliage of plants in the Myricaceae can be deciduous or evergreen, and the leaves are commonly fragrant when crushed. The flowers are small and occur in catkin-like inflorescences, which are made up of either male (staminate) or female (pistillate) flowers. The fruits are a one-seeded berry or drupe, often with a thick, waxy coating.
One of the most interesting characteristics of species in the sweet gale family is their ability to fix atmospheric nitrogen gas (N2-sometimes known as dinitrogen) into ammonia (NH3), an inorganic form of nitrogen that can be utilized by plants as a nutrient. The nitrogen fixation is carried out inside of specialized nodules on the roots and rhizomes of these plants. This is done by the enzyme nitrogenase, which is synthesized by bacteria that live in a mutualism with the vascular plant. The ability to fix atmospheric dinitrogen into ammonium is an extremely useful trait, because it allows species in the sweet gale family to be relatively successful in nutrient deficient habitats.
The most diverse genus in the Myricaceae is Myrica, of which several species occur widely in North America. The sweet gale (Myrica gale) is a common shrub along lakeshores and in other moist places over much of the temperate and boreal zones of North America and Eurasia. The sweet fern or fern-gale (M. asplenifolia) is widespread in eastern North America. Both the wax-myrtle (M. cerifera) and the bayberry or waxberry (M. carolinensis) of eastern North America produce fruits with thick, whitish, waxy coats. These fruits can be collected, the wax extracted using boiling water and then used to fragrantly scent candles.
See also Symbiosis.