•784 THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. 



receptacle is covered externally by the tube of the 4-6-sepalous calyx, is surmoiinted 

 by the segments of the calyx-limb, and bears upon it the 4-6 petals which alternate 

 with those segments. The gjTiseceum is composed of 3-8 connate carpels. The 

 3-8-locular ovary is adnate to the hollowed receptacle at the base only, or from the 

 base to the middle, or from the base to the top. An axis rises up in the middle 

 of the ovary and bears the placentas, which project into the separate loculi. The 

 andrcecium is composed of 1-2 whorls of 4-5 stamens each. At the base of each 

 anther is a spur-like appendage; dehiscence is apical by 1 or 2 small holes (see 

 fig. 216 '^, p. 91). The pollen is powdery. The fruit is a berry or a capsule which 

 dehisces by valves. The seeds contain no endosperm. 



The Melastomales belong chiefly to tropical America. Fossil remains have not 

 been identified with certainty. The number of species ascertained to exist at the 

 present time is about 2000. 



Alliance LX. — Lythrales. 

 Families: Lythracece, GwpheacecB, and Lagerstrcemiacece. 



Annual or perennial herbs, shrubs, and trees with opposite or whorled foliage- 

 leaves. Laminae entire, with pinnate venation. Flowers hermaphrodite, actino- 

 morphic or zygomorphic, with calyx and corolla. The cup-shaped or tubular 

 receptacle is covered externally by the tube of the 3-16-sepalous calyx, the 

 segments of which project beyond it and alternate with the 3-16 petals which are 

 borne upon the receptacle. The gynseceum is composed of 2-6 connate carpels. The 

 2-6-locular ovary is free, and is situated at the bottom of the hollow receptacle. 

 An axial column rises up in the middle of the ovary and bears the placentas, which 

 project into the separate loculi. The andrcecium is composed of 1-2 whorls of 3-16 

 stamens each. The anthers have no appendages, and dehisce by longitudinal slits. 

 The pollen is adhesive. The fruit is a capsule coated by the cup-shaped receptacle. 

 The seeds contain no endosperm. 



The Lythrales are distributed in all quarters of the globe. They exhibit greatest 

 variety in tropical America. Li the North Temperate Zone they are represented 

 by the genera Lythrum, Peplis, and Didiplis. No fossU remains are known. The 

 number of identified species now living is about 400. 



Alliance LXI.— HygrobisB. 

 Families: HippuridacecB, Callitrichacece, Myriophyllacece, Gunneracece, Trapacece. 



Herbs and under-shrubs living in water or in wet places. Flowers hermaphro- 

 dite, pseudo- hermaphrodite, monoecious, and dioecious; actinomorphic. Floral- 

 leaves inconspicuous, in 1-2 whorls of 2-4 leaves each. Gynceceum of one carpel 

 or 2-4 connate carpels. The under half or the whole of the 1-4-locular ovary is 

 adnate to the sepals, which cohere so as to form a cup. Each loculus contains one 

 ovule in its inner angle. The andrcecium is composed of 1-8 stamens. Th3 fruit is 



