1982 A TEXTBOOK OF THEORETICAL BOTANY 



with very narrow leaves, giving a superficial resemblance to a lichen. In 

 Tillandsia and Puya the ovary is superior, though in Ananas and Aechmea 

 it is inferior. 



ZINGIBERALES 



The Zingiberales are large perennial herbs with persistent rhizomes and 

 large glabrous leaves with a well-developed sheath, a long stalk and a 

 pinnately veined lamina. The flowers are large and showy, each is herma- 

 phrodite and zygomorphic or asymmetrical. The perianth is in two whorls, 

 either petaloid or separable into calyx and corolla. The stamens are usually 

 five or six in number but often only one is functional, the remainder be- 

 coming petaloid. The ovary is composed of three carpels, generally trilocu- 

 lar, with one or many ovules and axile placentation. The seeds, which are 

 sometimes arillate, contain endosperm and are enclosed either in a capsule 

 or a berry. 



The plants are tropical or subtropical and are found in swampy 

 forest districts. Several are extremely striking, some are of economic 

 importance and others are cultivated in greenhouses where space permits. 



The term Zingiberales, as here used, is due to Hutchinson and replaces 

 the Englerian order Scitamineae. Bentham and Hooker placed all the 

 members in a single family of the latter name. Later writers, including 

 Hutchinson, recognize a number of families of which we shall consider 

 briefiy the following: Musaceae, Zingiberaceae, Cannaceae and Marantaceae. 



The Musaceae are perennial herbs which perennate by underground 

 rhizomes and often attain very large size. The aerial shoot may reach 

 100 ft. in Ravenala madagascariensis, the Traveller's Tree, while in other 

 genera the axis is made up of the long, stitT leaf sheaths, which are rolled 

 round one another and conceal the short stem which finally elongates and 

 bears the inflorescence. The leaves are either radially arranged or are 

 restricted to two rows. They are very large and consist of a strong sheath 

 separated by a petiole from an enormous ovate blade. The blade has a 

 strong midrib from which are given off parallel veins to the margin. The 

 flowers are protected by great spathe-like bracts which are often coloured. 

 The inflorescence may be simple or compound and bears flowers which are 

 often brightly coloured. These flowers are zygomorphic and are either 

 hermaphrodite or may become unisexual due to the abortion of either 

 stamens or pistil. The perianth is petaloid and composed of two series of 

 free, or else more or less coherent parts. The stamens are free, five or 

 rarely six in number. The ovary is inferior and trilocular, containing 

 numerous anatropous ovules. The fruit is a berry or sometimes a loculicidal 

 capsule. The seeds often possess fleshy or hairy arils. The embryo is straight 

 and immersed in mealy perisperm. 



The family contains six genera and about 150 species, which are distri- 

 buted throughout the tropics. Three genera are worthy of mention, Musa, 

 Ravenala and Strelitzia. Musa contains about eighty species which may 

 grow to a height of 10 to 20 ft., with false aerial stems arising from a 



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