658 A TEXT-BOOK OF BOTANY. 



hairs which are very irritating and cause a dermatitis similar to that 

 produced by poison ivy. 



A number of the primulas have been examined chemically. 

 The subterranean parts of Primula officinalis contain two crystal- 

 line glucosides, primeverin and primulaverin, which by the action 

 of the ferment, primeverase, produce an anise-like odor. The 

 odors of the other species of Primula are probably due to distinct 

 glucosides: (a) one producing an anise-like odor, as in P. offici- 

 nalis, P. capitata, and P. denticulata; (b) one producing the odor 

 of methyl salicylate, as in P. longifiora, P. clatior, and P. vulgaris; 

 (c) one producing the odor of coriander, as in P. auricula, P. 

 panouica, and P. Pali)iuri. The flowers of a number of species 

 are light in color and somewhat luminous in the dark. 



b. PLUMBAGINACE^ OR LEADWORT FAMILY.— 

 Perennial, mostly acaulescent herbs, growing in saline locations. 

 Sea lavender or marsh rosemary (Liinonium Carolinian urn) is 

 found in the salt meadows from Labrador to Texas. The plant 

 is reported to contain tannin and has been used in medicine. 



III. ORDER EBENALES. 



This order includes three families which are chiefly indig- 

 enous to the Tropics. The leaves are alternate, and the flowers 

 vary in the different families, the fruit being a berry or drupe. 



a. SAPOTACE^ OR SAPODILLA FAMILY.— The plants 

 usually have a milky latex, and many of them yield gutta-percha, 

 of which the following may be mentioned: Palaquium Gutta, P. 

 oblongifolium, P. borncensc and P. Treubii, all growing in the 

 East Indies. The latex is obtained by incising the trees and collect- 

 ing the exuding juice in suitable vessels. It soon coagulates and 

 forms grayish or reddish-yellow hard masses, which are plastic 

 at 65° to 70° C. Owing to the fact that the material is plastic 

 when heated and firm and tenacious when cold, it is used for a 

 variety of purposes, as in the manufacture of surgical instruments 

 and as a material for filling teeth. Gutta-percha as it exudes from 

 the tree is supposed to consist of a terpene-like hydrocarbon, 

 which on coagulation is oxidized, forming a number of resinous 

 compounds. The plants of other genera of this family also yield 



