Other Topics
Trees and shrubs of Moraceae are primarily tropical, with temperate trees represented by Morus, Broussonetia, and Maclura (1).
The Mulberries, comprising about 10 species, are monoecious or dioecious trees or shrubs. They bear the staminate and pistillate flowers on different branches of the same tree or on different trees; these flowers are minute, and the staminate ones are in elongated cylindric spikes (2). The origins of the Mulberry tree (M. alba) are in China, Japan, Thailand and Malaysia. The tree is now found throughout the world. Only 2 species are native to North America, but several others have been introduced.
The Red mulberry (M. rubra), closely related to the Mulberry or White mulberry tree (M. alba), is native to eastern North America, from southernmost Ontario and Vermont south to southern Florida and west to southeast South Dakota and central Texas (3-4). The White mulberry (M. alba) is a native of China, where it is grown for feeding silkworms. It is also widely cultivated in the United States and Canada, occurring in fruit-bearing and ornamental varieties (2). Paper mulberry, B. papyrifera is native to Asia but grown elsewhere, including the USA. M. alba and B. papyrifera have a predilection for warmer regions, extending to the US West Coast (1).
Red mulberry is a medium-sized deciduous tree, growing 10-15 m tall and with a trunk up to 50 cm in diameter. It may, rarely, reach 20 m in height. The leaves are variable but usually alternate, 7-14 cm long, 6-12 cm broad, simple, broadly cordate, with a shallow notch at the base, unlobed on mature trees, often with 2-3 lobes on young trees, and with a finely serrated margin (1). Red mulberry leaves are a deeper bluish green, and M. alba a lighter green (1.2).
Female and male flowers are found on dense catkins, on the same or separate trees. Pollination for most Mulberries is in April and May, beginning in March in the southern states, and later, extending into June, in the northern states (1,3-4). Each male flower has 4 stamens bent inward in the bud but straightening elastically and becoming exserted at maturity. They shed large amounts of pollen, which is occasionally the cause of hayfever.
The fruit is a compound cluster of several small drupes, similar in appearance to a Blackberry but somewhat elongated, 2-3 cm long, red ripening to dark purple, edible and very sweet. The fruit ripens in June or July.
