326 Minnesota Plant Life. 



of which Minnesota species are known. Many of the families 

 are small exotic groups of plants, but among them are some 

 important economic varieties. The tea-plant, a member of the 

 tea family, cultivated in Japan, China and Ceylon, is classified 

 here, also the camphor plant, the marcgravias, the tamarisks, 

 the passion-flowers and the begonias. The families represented 

 in Minnesota are the St. John's-worts, with about a dozen 

 species, the rock-roses, with three or four species, and the vio- 

 lets, with about twenty species. 



St. John's-worts. The St. John's-worts are herbs with oppo- 

 site leaves, which are always marked with glandular dots or 

 small black specks. The flowers are borne in panicles or cymes 

 at the apex of slender stems. In each flower there are five sepals 

 and five petals, with a number of stamens sometimes united 

 into clusters. The ovary is one-chambered, with from three to 

 five interior longitudinal ridges, along which the numerous seed- 

 rudiments are attached. At the top of the capsule, which is 

 generally pyramidal-ovoid in form, from three to six separate 

 stigmas are borne. In some of the Minnesota varieties the 

 longitudinal interior crests of the fruit-rudiment project clear 

 to the centre, thus making a three- to five-chambered capsule. 

 The flowers are regular in appearance. The different varieties 

 of St. John's-worts may be recognized by their general habit 

 of growth ; by the sizes and shapes of the leaves ; by the char- 

 acter of the flower-cluster, which, as has been said, is either 

 flat-topped or panicled; and by the cross section of the fruit, 

 which is, when mature, in all instances a dry capsule some- 

 times one-chambered, sometimes three-chambered and some- 

 times five-chambered. In all these the leaves are ovate, slender 

 or elongated. One variety, the marsh St. John's-wort, is found 

 only in swamps. It may be recognized by its three-carpeled 

 red capsule. 



Rock-roses. The rock-roses include three or four plants, of 

 ledges or barren soil, known as frostweeds, Hudsonias, pin- 

 weeds, beach heathers or false heathers. The frostweed, which 

 is a pretty common plant throughout the state, is a woody herb 

 one or two feet in height with two kinds of flowers, some with 

 petals and clustered in terminal cymes, the others much smaller, 

 without petals, almost sessile in the axils of the leaves. The 



