SUMACH AND HOLLY 209 



and Texas. It is neither handsome nor especially useful, and often 

 looks very frowsy because of its susceptibility to insect and fungous 

 infection. Its individual leaves are not unattractive and the plant 

 is interesting as an illustration of quiet and persistent aggressiveness. 

 Inhabiting dry soils, its underground stems penetrate for yards in 

 every direction, often growing to considerable size, and sending 

 up new plants from the nodes. Many a New England pasture has 

 been ruined by it, and it cannot be eradicated until every vital 

 spark beneath the sod has been uprooted. The fruit is not hand- 

 some, and the leaves, usually of entire leaflets, pinnately arranged, 

 have the stem margins winged between the leaflets, ijiaking it 

 readily recognizable. Both the leaves and the bark contain large 

 amounts of tannin and they are sometimes systematically collected 

 and used in tanning. 



The geological history of the sumachs goes back to the far off 

 days of the dinosaurs, and ten or a dozen widely scattered species 

 have been found in the rocks of the Upper Cretaceous period. At 

 the beginning of Upper Cretaceous time there was a sumach in 

 Saxony, and two in Kansas and Texas, this wide distribution 

 showing that still earher species await discovery. No sumachs 

 have been described from the Upper Cretaceous of western Green- 

 land where so many ancestral trees have been found, although it 

 is probable that some of the fossil leaves found in that region and 

 identified as myricas may represent sumachs instead. Somev/hat 

 later in the Upper Cretaceous additional species of sumach occurred 

 in South Carohna, Long Island, Wyoming, Bohemia and Italy. 



About 13 forms are known from the Eocene. In the earher 

 part of that dawning Tertiary time sumachs occurred in Dakota, 

 Colorado, Wyoming and Yellowstone Park. In later Eocene time 

 they are known from Colorado, from central Europe, and in north- 

 ern lands in Alaska, Greenland and Iceland. Four different forms 

 have been found in the upper Eocene rocks of Greenland, which is 

 presumptive evidence that they already existed in that region in 

 antecedent Upper Cretaceous times. 



The number of species of sumach was doubled during succeeding 

 Ohgocene times. As is the case with so many tree histories, the 



