A Witch's Broom of the Desert. 



61 



to grow. Such bogs are always supplied with water from 

 underground sources, or by streams that spread out over a con- 

 siderable area of mountain slope. One other fact should be 

 mentioned about bogs, and that is, their temperature is known 

 to be low, and the expression "cold bogs" is frequent in our 

 manuals. It has been proved that the low temperature of 

 bogs is not due to evaporation from the surface, but is due 

 rather to a persistence of the winter cold and ice which in such 

 a large non-conducting mass would last through the summer 

 months. It is not surprising, therefore, that arctic and glacial 

 plants are preserved in such bogs, while the surrounding vege- 

 tation has undergone marked changes since the close of the 

 glacial period. 



A WITCH'S BROOM OF THE DESERT. 

 By Paul C. Staxdley. 



One of the most common shrubs in the southern and south- 

 western parts of New Mexico is Ephedra trijurca Torr. It 

 occurs upon the sandy mesas and is especially abundant where 

 they are cut by arroyos. The plant is known among the Mexi- 

 cans as "popotillo" or "canatillo." With them, as well as 

 among Americans, it is reputed to be a cure for venereal diseases. 

 It is reported that a tea made from one of the species of the 

 genus is used in Mexico as a remedy for kidney diseases, and the 

 tea is even said to be used by some people as a beverage, although 

 it would seem that it could not have an especially pleasant 

 taste since the green stems when chewed have very much the 

 flavor of green persimmons. This bitter taste is probably due 

 to the abundance of tannin in the stems. 



The shrub is a rather prominent feature of the landscape 

 in some places and attracts notice because of its lack of leaves. 

 For this same reason the witch's broom, illustrated here, is con- 

 spicuous wherever it appears. The cause of this interesting 

 growth is a fungus, Aecidium minus (Berk.), according to a 

 determination made by the late Dr. Underwood. It appears 

 in this vicinity in late summer after the beginning of the rainy 

 season. It was very abundant during the summer of 1907, 

 but less so, apparently, during the past season. The bright 



