ARISTOLOCHIACE^. 89 



EXCLUDED SPECIES. 



THESIUM INTERMEDIUM. Schrad. 



" Said to be a native of Britain." {Bah. Man. Brit. Bot. ed. vi. 

 p. 298). I have seen no specimens, nor can I hear of anyone 

 who has. 



THESIUM HUMILE. Vald. 



Professor Babington gathered two specimens of this plant somewhere 

 near Dawlish in Devonshire, in 1829, but it was probably not indi- 

 genous. 



ORDER LXVI.— ARISTOLOCHIACEiE. 



Herbs or shrubs, in the latter case generally twining, and with the 

 wood not in evident rings. Leaves alternate, sometimes 2 and sub- 

 opposite, stalked, generally cordate, entire, rarely pedatifid. Stipules 

 opposite the leaves, or leafy or absent. Flowers perfect, rarely uni- 

 sexual, solitary or in fascicles in the axils of the leaves, rarely in 

 racemes. Perianth single, usually coloured, with the base of the tube 

 adhering to the ovary, tubular, with the limb very irregular and 

 oblique, entire or 2- or 3-cleft, or regular and 3-toothed; segments 

 with valvate 03stivation. Petals absent. Stamens definite, usually 

 G or 12, rarely 9; filaments very short and often adhering to the style; 

 anthers 2-celled, longitudinally dehiscent. Ovary syncarpous, adhering 

 to the bottom of the tube of the perianth, generally 6 -celled, more 

 rarely 3-celled, and very rarely 4-celled; ovules numerous, ascending 

 or horizontal from the axis of the ovary, anatropous ; style very short 

 and thick; stigmas G, radiating above the stamens. Fruit a capsule 

 or beriy loculicidally dehiscent, rarely indehiscent. Seeds numerous, 

 with a membranaceous testa; albumen dense, fleshy or somewhat 

 horny; embryo minute; cotyledons scarcely apparent until germi- 

 nation ; radicle inferior. 



GENUS /.—A S A R U M. Linn. 



Perianth bellshaped, with the tube wholly adherent to the ovary, or 

 suburceolate and adhering to the ovary only by its base ; limb regular, 

 [3-cleft or 3-partite. Stamens 12, the filaments more or less distinct 



VOL. VIII. N 



