74 BOTANY. 



Sub-order 4. Aimecc. Naked flowers with a spadix and spatha, i ?. 

 anthers sessile, ovules several, fruit succulent, seeds pulpy, Arum triphyllum 

 is the well known Indian Turnip : A. maculatum, or the European Wake 

 Robin, is represented in pi. 55, ßg. 2 ; a, the entire plant, b, the spadix with 

 its flowers ; c, anther ; d, the disk ; e, an ovary ; /, the lower part of the 

 spadix with fruit ; g; one of the fruit cut transversely ; h, a seed in longitu- 

 dinal section. Other genera are Peltandra, Calla, Collocasia, Calladium. 



Order 15. Pandanace^ or Screw Pines. Flowers unisexual or polyga- 

 mous, covering the whole of the spadix. Perianth 0, or a few scales. Male 

 flowers : stamens numerous ; filaments with single anthers, which are two- to 

 four-celled. Female flowers : Ovaries one-celled, united in parcels ; ovules 

 solitary or numerous, anatropal ; stigmas sessile, equal to the carpels in 

 number. Fruit either fibrous drupes collected into parcels, or berries. Seeds 

 solitary in the drupes, numerous in the berries ; embryo at the base of fleshy 

 albumen ; radicle next the hilum. Trees or bushes, sometimes with adventi- 

 tious roots, long, imbricated, amplexicaul leaves, usually with spiny margins 

 and backs. Natives of tropical regions. 



The flowers of some of the plants are fragrant, and their seeds are some- 

 times used as food. The juice has in some instances astringent properties. 

 The species of Pandanus are remarkable for their aerial roots, with large cup- 

 like spongioles. These roots are sent out regularly from all parts of their 

 stems, and appear like artificial props. Their spormoderm has numerous 

 raphides. Their leaves are arranged in a spiral manner in three rows, and in 

 their aspect they have some resemblance to those of the pine-apple, hence the 

 name screw-pine. Pandanus candelabra is the chaiidelier-tree of Guinea, 

 and is so called on account of its mode of branching. 



This order is divisible into two sub-orders. 



Sub-order 1. Cydanthecc. with fan-shaped or pinnate leaves. Flowers most 

 generally provided with a perianth. Examples : Carludovica, Cyclanthus, 

 Nipa, Wettinia. 



Sub-order 2. Eupandanea. Leaves simple or undivided, perianth none. 

 Examples : Pandanus, Frcycinetia. 



b. Perianth free^ Ovary superior, Flowers nsnally hermaphrodite. 



Order 16. BuTOMACEiE, the Flowering-rush Family. Perianth of six 

 parts, in two verticils ; outer usually herbaceous ; inner petaloid. Stamens 

 definite, or 00, hypogynous. Ovaries three, six, or more, distinct or united, 

 one-celled : ovules 00 ; stigmas simple, as many as the carpels. Fruit con- 

 sisting of several follicles, Avhicli are either distinct and beaked, or combined. 

 Seeds 00, minute, attached to the whole inner surface of the pericarp, exalbu- 

 minous ; embryo often curved like a horse-shoe ; radicle next the hilum. 

 Aquatic plants, often lactescent, with parallel-veined leaves, and frequently 

 umbellate flowers. They are chiefly found in northern countries, and some of 

 them have acrid and bitter properties. The principal genera are Butoraus, 

 Limnocharis, and Hydrocleis. 



Order 17. Alismace^, the Water plantain Family. Perianth in six 

 74 



