388 SYSTEMATIC BOTANY. 



perianth free from the 3-celled ovary; the 3 or 6 mostly unequal or 

 dissimilar stamens inserted in its throat. They are separated from 

 Liliacese chiefly by the irregular flowers, the persistent perianth rolling 

 inwards after flowering, and by the mealy perisperm of their seeds. They 

 are natives of North and South America, India, and Africa, and do not 

 appear to have any important properties- Some of the Pontede.rice are 

 usually grown in stoves where there is a tank, on account of their blue 

 flowers. 



consist of four species of Mayaca, little Moss-like plants 

 occurring in America, from Brazil to Virginia, separated from Comme- 

 lynacese on account of their habit, 1-celled anthers, 1-celled ovary with 

 parietal placentas, and the carpels opposite the inner lobes (petals) of the 

 perianth. They have no useful properties. 



GILLIESIACEJE are a small Order of plants of somewhat anomalous 

 structure, related to Liliacese (see p. 385) ; they are bulbous herbs with 

 spikes of flowers which have a double circle of petaloid envelopes, 6 or 8 

 subulate processes, then a cup-like or labelloid organ bearing 3 or 6 anthers 

 on its inner surface, and a 3-celled ovary. Lindley regards the petaloid 

 envelopes and subulate processes all as bracts, and the structure on which 

 the anthers are borne as the perianth. Other authors are opposed to this 

 view. Gilliesia, Lindl., and Miersia, Lindl., are both Chilian genera. 



PHILYDRACEJE are herbs with fibrous roots, ensiform leaves with 

 equitant bases ; flowers within a persistent spathaceous bract, with a 3- 

 parted petaloid perianth ; 2 upper segments coherent into one ; 3 coherent 

 stamens, of which the 2 lateral are barren and petaloid, and the middle 

 has a two-celled anther, the whole adherent to the anterior lobe of the 

 perianth ; the pollen-cells are coherent in masses of four ; the ovary supe- 

 rior, 3-celled, the odd cell anterior, with axile placentas; seeds numerous, 

 with an embryo in the axis of fleshy perisperm. This Order consists of 

 two plants, Philydrum lanuginosum (Australia) and Hetceria pygmaa 

 (China), exhibiting, with a superior ovary, appearances analogous to those 

 in the epigynous group of Orchidaceae and their allies. Lindley regards 

 them as related to Commelynaceaa and Xyridacese ; but they would appear 

 to be rather a kind of peiigynous ZingiberaceaB. They have no known 

 uses. 



B. APOCAEPI^:. 

 Carpels usually distinct ; seed aperispermie. 



ALISMACEJ^. 



Coh. Potamales, Hook. Fig. 473. 



Diagnosis. Marsh-herbs, mostly with broad petiolate 

 leaves and scape-like flowering stems ; flowers perfect or 

 monoecious, with a double perianth, consisting either of 

 a green calyx and a coloured deciduous corolla, or of 2 

 circles of green scales, each of three pieces (fig. 473) ; 

 ovaries 3, 6, or numerous, more or less distinct, and 

 separating into as many nuts ; seeds campy lotropous or 

 anatropous ; embryo doubled, hook-shaped, or straight, p]an of flower of 



without perisperm. Triglochin: x, bract. 



