THALAMIFLOR/E. 215 



DROSERACE/E are bog-herbs, mostly glandular-haired, with regular 

 hermaphrodite 5-merous flowers and marcescent calyx and corolla ; sta- 

 mens as many as the petals, or indefinite, hypogynous or perigynous ; the 

 anthers fixed by the middle, extrorse j ovary free, 1-celled; ovules 

 numerous, inverted ; styles as many as the placentas or connate ; pod 

 1-celled, placentas parietal or basilar ; the embryo minute, at the base of 

 fleshy perisperm. Illustrative Genera : Drosera, L. ; Aldrovanda, Monti ; 

 DioiKEct, Ellis. 



Affinities, &c. The interesting but not very numerous plants of this 

 Order are remarkable for the circinate curvature of their flower-stalk?, 

 which, together with the absence of stipules, the extrorse anthers, divided 

 styles, &c., separates them from the Violacese, which they approach ; 

 they are connected with Hypericacese by Parnassia, and have some affinity 

 to Oistaceae and Turneraceae. Bentham and Hooker place them near the 

 Saxifrages. These plants are found in bogs or marshes in most parts of the 

 globe, excepting the Arctic regions. Their most interesting charac- 

 ters reside in the leaves, which in Drosera (Sun-dews) are covered with 

 beautiful glandular hairs, which have a spiral vessel running up their 

 stalks and secrete a digestive fluid. They are also endowed with the power 

 of motion when touched, so that an insect alighting on the leaf is unable 

 to make its escape owing to the viscid fluid exuded from the glands. 

 The hairs then bend over the insect, which becomes dissolved by the acid 

 fluid, and ultimately absorbed. Aldrovanda vesiculosa, a native of South 

 Europe, has curious whorled, cellular, spoon-shaped leaves. Dioncea muci- 

 pula, the Veuus's Fly-trap of the North-American bogs (occasionally 

 cultivated in stoves here), is well known for the remarkable irritability and 

 digestive properties of the lamina of the leaf, the two lobes of which 

 close upon any object touching the upper face. The Droseracese are said 

 to be acrid. 



VIOLACE^E. THE VIOLET OEDEB. 

 Coh. Parietales, Benth. et Hook. 



Diagnosis. Herbs or shrubs : leaves alternate, usually stipulate ; 

 flowers regular or irregular, hermaphrodite, with a somewhat 

 irregular, generally 1-spurred corolla of 5 petals : stamens 5, 

 hypogynous, with adnate introrse anthers connivent over the 

 pistil, connective of the anther usually prolonged ; style and stigma 

 single ; pod 1-celled ; 3-valved, with 3 parietal placentas in the 

 middle of the valves ; seeds perispermic ; embryo straight. 



Character. 



Thalamus flat or slightly rounded. Calyx : sepals 5, persis- 

 tent, usually elongated at the back, imbricated in aestiva- 

 tion. Corolla: petals 5, hypogynous, equal or unequal, one 

 usually spurred, withering-persistent ; obliquely convolute in 

 aestivation. Stamens 5, alternate with the petals, or 

 occasionally opposite, inserted on an hypogynous disk, often 

 unequal; anthers 2-celled, introrse, separate or cohering, and 



