144 



FAMILIES OF FLOWEEING PLANTS 



Family Erytliroxylaceae. Redwood family. Contains two genera, 

 Erytliroxylori, witli about 90 species, natives of South America and 

 Africa, and Aneidophus, vnth a single species, A. Africaua, a shrub of 

 Upper Guinea. The i^lants are all shrubs or trees with small flowers, 

 ha\'ing 5 sepals and petals, and 10 stamens, the latter monadelphous, 

 as we noted those of the Leguminosae to be. The fruit is a drupe con- 

 taining a single seed. The bark, as the name indicates, contains a red- 

 dish coloring matter, from which a dye is prepared. The most inter- 

 esting of the Erythroxylons is undoubtedly E. Coca, which yields the 

 famous drug known as cocaine (Fig. 125 no. 3). 



Family Zygophyllaceae. Caltrop or Bean-caper Family. Con- 

 tains about 20 genera and 150 species, of wide distribution in warm and 

 tropical regions. They are herbs, shrubs, or trees, with leaves mostly 

 opposite and more or less divided. The flowers are perfect, with the 

 parts chiefly in fives; ovary 4-12 celled, capsular or baccate in fniit. 



Several low herbs with pinnate leaves 

 and yellow flowers, belonging to the re- 

 lated genera Trihtdus and Kcdlstroemia, 

 are common in the southwest, as is also 

 the interesting creosote bush {GovUlea 

 3Iexicaua). So strong is the odor of the 

 resinous principle in this plant, that I 

 have known herbarium specimens many 

 3^ears old to cause a violent attack of hay- 

 fever in a person subject to that disease. 

 The shrub thrives in the desert region of 

 Arizona and New Mexico and Mexico, and 

 is very ornamental when in full bloom, 

 although valueless either as fuel or for 

 forage (see Fig. 126). The genus Guiacum 

 consists of trees noted for the remarkable 

 hardness of their wood, and for the resin 

 which they contain. G. officinale, which is highly ornamental in culti- 

 vation, with its blue flowers and pinnate leaves, yields the heavy wood 

 known as lignum-\dtae. The leaves of G. sanctum are frequently used 

 in the West Indies as a substitute for soap. 



The seeds of several Old World shrubs or herbs belonging to this 

 family, notably Zygopliyllum Fabago, the bean caper, and Peganum Har- 

 mala, are used as vermifuges. 



Family Cueoraceae. Cneorum Family. Contains the single genus 

 Cneorum, comprising about 12 species of maritime shrubs in the Medi- 

 terranean region and in the Canary Islands. They have yellow flowers 

 with 3-4 petals, 3-4 stamens, and a 3-4-lobed ovary. The fruit is pecu- 



^Aj7>. 



Fig. 126. Creosote bush {Covillea 

 Mexicana); flowering branch, one-half 

 natural size. Original. 



