154 



FAMILIES OF FLOWEKING PLANTS 



Family Busaceae. Box Family. This was formerly united with 

 the Spurge Family above described, from which it may be distinguished 

 by the absence of milky juice. There are 6 genera and 30 species; the 

 familiar evergi-een known as box is Buxus sempeyvirens, a member of 

 the typical genus. In the Allegheny mountains grows a curious herb, 

 the Allegheny mountain sj^urge (see Fig. 132), which also belongs to 

 the family; the spikes of staminate flowers are quite fragrant. The 

 only other kno^uoi species of Pachysavdra is Japanese, the genus thus 

 affording another instance of that curious analogy between the Japan- 

 ese and the eastern North American flora. 



Family Empetraceae. Crowberry Fam- 

 ily, These are low, evergreen shrubs of 

 heath-like aspect, with small axillary or clus- 

 tered dioecious flowers succeeded by berry- 

 like drupes. Sepals 3, petals 2 or 3 or want- 

 ing; stamens usually 3. There are only 

 three genera, Empetrum, Corema and Gorrig- 

 iola. High up in the arctic regions, extend- 

 ing southward to our northern border, grows 

 the crowberry (see Fig. 133), covering dense 

 patches of ground, its black berries affording 

 an abundance of food for the Arctic birds. 

 Another si^ecies is found in Antarctic South 

 America. Scarcely less remarkable is the 

 distribution of Corema, one species of which 

 {C. Conradii) occurs in a few isolated stations 

 from Newfoundland to New Jersey, the other 

 in southwestern Europe. The third member 

 of this family, Corrigiola, is a monotypic 

 genus of Florida. 



Family Coriariaceae, Coriaria Family. Consists of the single 

 genus Coriaria, with 8 species, natives principally of the Old World, 

 although one species occurs in Peru. They are shrubs Avdth ribbed 

 leaves and clusters of flowers having the parts in fives. The fruit con- 

 sists of 5 one-seeded carpels, surrounded by the ]3ersistent fleshy petals. 

 The fruit of the common European species {C. myrtifolia) is poisonous, 

 but some of the Oriental forms have edible fruits, though the seeds are 

 usually poisonous. 



Family Limnanthaceae. False Mermaid Family. These are deli- 

 cate annual herbs of two genera. One, Limnanthes, is confined to the 

 Pacific States, and contains about 6 species; the other, Floerl-ea, is a 

 marsh plant rather widely distributed through the United States. The 

 family is distinguished by the alternate, pinnately divided leaves, and 



Fig- 133- The crowberrj' {Em- 

 petrum nigrum). Original. 



