460 SYSTEMATIC BOTAXV. 



properties. Some of the Droseras are said to be poisonous to 

 cattle, but there is no satisfactory proof of such being the case. 

 It has been supposed that some of the Droseras would yieki 

 valuable dyes, because they communicate a brilliant purple 

 stain to the paper upon Avhich they are dried, and also from 

 the circumstance of yielding a yellow colour when treated with 

 ammonia. The plants of the order are, however, chiefly inte- 

 resting from the peculiar ii'ritability of the hairs on their leaves. 

 Thus the Sun-dews (Z>/-ose/-rts), are fringed with beautiful glan- 

 dular hairs, which close more or less in different species when 

 insects alight upon them ; while Dioncea muscipula (Jig. 352), a 

 native of North America, has two-lobed leaves, each of which 

 is furnished on its upper surface with three stiff hairs, Avhich, 

 when touched, cause the two halves of the leaf to collapse and 

 enclose the object touching them. This plant is sometimes 

 cultivated in our stoves, and is commonly known as A^enus's 

 Fly-trap. 



Natural Order 2.3 Frankeniace^. — The Frankenia Order. — 

 General Character. — Herbs or under shrubs, much branched. 

 Leaves opposite, exstipulate. with a membranous sheathing 

 base. Flowers sessile. Calyx tubular, with 4 or 5 divisions, 

 equal, persistent. Petals 4 or 5, distinct, imbricate, often 

 appendaged, unguiculate, hypogynous. Stamens 4 or 5, or 

 twice as many as the petals, hypogynous, distinct ; anthers 

 versatile. Ovary 1 -celled, superior ; style 2, 3, or 4-fid ; ovules 

 numerous, anatropal ; placentas parietal. Fruit capsular, 

 1 -celled, many-seeded, 2, 3, or 4-valved, enclosed in the calyx. 

 Seeds numerous, very minute ; embryo straight, erect, in the 

 middle of albumen. 



Diagnosis. — Herbs or undershrubs, much branched, with 

 opposite exstipulate leaves, and sessile flowers. Calyx tubular, 

 furrowed, persistent. Petals unguiculate, 4 or 5, hypogynous. 

 Stamens hypogynous, distinct. Ovary superior, 1 -celled, with 

 parietal placentas. Fruit capsular, 1-celled, enclosed in the 

 calyx, and dehiscing in a septicidal manner. Seeds numerous ; 

 embryo straight, erect, in the middle of albumen. 



Distribution, ^c. — The plants of this order are scattered over 

 the globe, except in tropical India and North America, but they 

 chiefly occur in the south of Europe and north of Africa. Ex- 

 amples : — Frankenia, Beatsonia. There are 4 genera, and 24 

 species mentioned by Lindley. 



Properties and Uses. — Unimportant. They have been reputed 

 mucilaginous and slightly aromatic. The leaves of a species 

 of Beatsonia are used at St. Helena as a substitute for tea. 



Natural Order 24. Tamaricace^. — Tlic Tamarisk Order. 

 General Character. — Shrubs or herbs. Leaves alternate, 

 scaly, entire, usually pitted. Flowers in spikes or racemes. Calyx 

 4 or 5 ])artcd, ])ersistent, imbricate. Petals distinct, adherent to 



