XCI. CALLITRICHINE^. 417 



Stem herbaceous. Leaves all radical, petiole long, blade usually reniform, 

 crenulate, hairjw Flowers § , or imperfect, monoecious or dioecious, ebracteate ; 

 scape bearing a very close spike, composed of several spikelets, each furnished with a 

 bract. Perianth 4-partite, 2 segments small, tooth-shaped, alternating with 2 

 larger, petaloid, caducous, sometimes obsolete, reduced to scales in the $ flowers. 

 [Perianth otherwise described as, Caltx-lobes 2-3, equal or unequal, or 0. Petals 

 or 2, hooded, j Stamens 2, opposite to the petaloid segments ; filaments short [or 

 long] ; anthers 2- celled, [basifixed], dehiscence longitudinal [lateral]. Ovary in- 

 ferior, 1-celled ; styles 2, covered with stigmatic papillae ; ovule solitary, pendulous 

 from the top of the cell. Fruit a drupe. Embryo minute, at the top of a fleshy 

 albumen ; radicle superior, 



GENUS. 

 * Gunnera. 



A. de Jiissieu considered tliat, in many cases, apetaldus and diclinous structures ■were to be regarded 

 as arrested conditions of perfect types, which masked affinities without annulling them; and this 

 explains the position he gives to Gunneracea, between AraliacecB and Coniem, which they approach in 

 their flower, which is hermaphrodite in some species, in their epigyny, the single pendulous anatropous 

 ovule in each carpel, the drupaceous fruit, and the minute embryo at the top of a fleshy albumen. The 

 same considerations establish the affinity of Qunneracem with HaloragetE ; in both these families may he 

 observed, on the one hand, a perfect organization ; on the other, the absence of petals, and the abortion 

 of the reproductive organs ; and the analogy is increased by the stigmatic papillje along the styles. 



The few spefties of this little group inhabit tropical Southern Africa and America, the high mountains 

 of tropical America, the Sandwich and Society Islands, Java, [Australia] and New Zealand. 



The fruit of Ounnera maerophylla is used in Java as a stimulant. The roots of G. scabra, called 

 Panque in Chili, and cultivated in Europe for the beauty of its leaves, which are sometimes more than 

 six feet in diameter, contain astringent principles, and are used in Chili for tanning skins, and as 

 an anti-dj'senteric. 



XCI. CALLITRICHINEJE, UveilU} 



Floating flaccid annual herbs, simple or branched, stem cylindric. Leaves 

 opposite, sessile, the lower [submerged] , often linear, the upper oval, 1-3-nerved, 

 entire, emerged, often rosulate ; stipules 0. Flowers g or monoecious-dioecious 

 by arrest, solitary and sessile in the axil of the leaves ; involucre diphyllous [or 0] , 

 of 2 lateral opposite curved somewhat fleshy and coloured [white] persistent or 

 deciduous leaflets. Perianth 0. Stamen posterior, rarely 2 antero-posterior, 

 inserted below the ovary in the ? flowers ; filament filiform, elongated ; anther 

 reniform, basifixed, 1-celled, opening at the top by an arched slit. Ovary free, at 

 first sessile, then stipitate, formed of 2 bilobed carpels with two 2-ovuled cells ; ^ 

 styles 2, distant ; stigmas acute, papillose over the whole surface ; ovules curved, fixed 

 to the central angle near the top of the cell ; micropyle lateral and internal, placed 



' See under Haloragew, p. 414.^Ed. cells, bvit considered as originally 2-celled, each cell being 



' The ovary is i-lobed and 4-cened with 1-ovuled divided into two by the inflection of its walls. — Ed. 



E E 



