THALAMIFLOK^. 239 



(which is developed in Hydrocerd) ; the two small lateral sepals, the spur, 

 and the double segment on the opposite side to the spur form an imbri- 

 cated calyx of five parts ; the odd petal opposite the two confluent sepals 

 is suppressed, and the others are generally combined into two 2-lobed 

 bodies, but are sometimes free ; in single flowers the stamens alternate with 

 these ; in double cultivated flowers a second corolline circle of five petals 

 sometimes appears in the place of the stamens, and the stamens alternate 

 again with these. The structure of the ovary and its mode of dehiscence 

 are also deserving of notice. The name of the genus Impatiens is derived 

 from the elasticity with which the capsule bursts when touched after the 

 seeds are ripe. The species are rather numerous. A few are scattered 

 over the globe; but the majority are East-Indian. Their properties are 

 unimportant. I. Balsamina is a valued tender annual plant ; I. Noli-me- 

 tanyere grows in the north of England ; and /. fulva (North America) is 

 naturalized in some places in Southern England. 



VIVIANACEJE are a small Order of South-American herbs or half- 

 shrubby plants, related to Gerauiaceae, but having a valvate calyx and 

 perispermic seeds. Properties unknown. 



:. GABDEN-NASTTTBTITTMS. 



Series Disciflorae ; Tribe Pelargonieae of Geraniaceae, Benth. et Hook. 



Diagnosis. Smooth trailing or climbing herbs with a pungent juice ; 

 leaves alternate, exstipulate j flowers axillary, irregular, perfect ; sepals 

 3-5, the upper or posterior one spurred ; petals 1-5 ; stamens 6-10, peri- 

 gynous, distinct ; ovary superior, of 3 or 5 cartels ; style single ; stigmas 

 3-5 ; ovules pendulous, 1 in each carpel ; fruit dry ; carpels separating 

 as indehiscent achenes from a central axis ; seeds large, aperispermic. 

 Illustrative Genera : Tropceolum, L. ; Chymocarpus, Don. 



Affinities, &c. A small Order of plants, natives of the temperate parts 

 of South America, related to Limnanthaceae, Malvaceae, and Geraniaceae, 

 and included in the latter family by Bentham and Hooker. The genus 

 Tropceolum contains the garden Nasturtiums, or Indian Cresses, notable 

 for their pungent juice, somewhat like that of Cruciferae. Various species 

 have a tuberous root : that of T. tuberosum is eaten in Peru. The spur 

 of the calyx of Tropceolum is curious, resembling that of Pelargonium, 

 but is free from the peduncle. In some cases it would seem to be a 

 tubular process from the receptacle. The flowers are mostly showy and 

 of great variety of colour. The Canary Creeper, T. pereyrinum or adun- 

 cum, may be noticed for the power of the full-grown plant to obtain its 

 nourishment apparently almost entirely from the atmosphere, and for its 

 climbing by twining its petioles, like Clematis. 



LIMNANTHACEAE, a small Order of North- American plants, are chiefly 

 distinguished from Tropaeolacese, with which they are associated in the 

 family Geraniacece by Bentham and Hooker, by their regular flowers, 

 erect ovules, and the adherence of the stamens to the calyx. Their 

 properties are analogous. Limnanthes (California) has showy flowers. 

 Flwkia (United States) is a mere weed. 



