MARE'S-TAIL TRIBE 95 



3. ISNARDIA 



I. /. palustris (Marsh Isnardia). The only British species. A 

 small, herbaceous plant, 6-8 inches long, with prostrate rooting 

 stems ; leaves ovate, smooth, stalked, and opposite ; and small 

 axillary sessile flowers, which are destitute of petals. Very rare. 

 Has been found only at Buxstead in Sussex, and in the New Forest. 

 Fl. July. Annual. 



4. CiRC/EA (Enchanter' s Nightshade) 



1. C lutetiana (Common Enchanter's Nightshade). A slender, 

 herbaceous plant 1-2 feet high, with a branched, downy stem ; egg- 

 shaped leaves, toothed and pointed, and hairy calyx. The roots are 

 creeping, the flowers small, white, with pink stamens, and are borne 

 in graceful branched racemes, and are succeeded by 2-lobed, hairy 

 seed-vessels. Damp shady places ; common ; often a troublesome 

 weed in damp gardens. Fl. July, August. Perennial. 



2. C. Alpina (Alpine Enchanter's Nightshade). Stem nearly 

 smooth ; leaves heart-shaped, toothed, shining. Closely resembling 

 the last, but smaller and less branched ; 5-8 inches high ; the fruit 

 is not so bristly, and is usually i-seeded. The leaves are remark- 

 able for their delicate texture, and when dried are nearly trans- 

 parent. Mountainous woods in the north. Fl. July, August. 

 Perennial. 



Natural Order XXVI 



HALORAGACE^. The Mare's-tail Tribe 



Calyx adhering to the ovary, and either expanding into 3 or 4 

 minute lobes, or reduced to a mere rim ; petals either minute and 

 placed on the mouth of the calyx, or wanting ; stamens either 

 equalling the petals in number, twice as many, or, when petals are 

 absent, 1 or 2 ; ovary with one or more cells ; stigmas equal in 

 number to the cells of the ovary ; capsule not opening ; seeds 

 solitary, pendulous. An unimportant Order, comprising about 

 eighty species of plants, scattered over most parts of the globe, 

 none of which have any economic use. They are for the most part 

 herbaceous aquatics, with inconspicuous flowers often destitute of 

 petals, and in one genus, Hippuris (Mare's-tail), composed of a 

 minute calyx, a solitary stamen, and a single seed. In several 

 species the stamens and pistils are in separate flowers. 



1. Hippuris (Mare's-tail). Calyx forming a minute, indistinctly 

 2-lobed rim for the ovary ; petals o ; stamen I ; style 1 ; seed I ; 



