[From the Bdllktin op thb Torkby B<itanical Club, 31 : 45-30. January, 1904] 



The spines of Fouquieria * 



Winifred J. RoniNsoN 



The six species now comprised in the genus Fouquieria occupy 

 collectively a region extending from the vicinity of the City of 

 Mexico northward into California, Arizona, New Mexico and 

 Texas. Nearly all of the species find their habitat in arid districts, 

 and the localities from which they have been reported may be 

 comprised within the southern extensions of the Chihuahuan and 

 Sonoran deserts. Among other adaptations, the various species 

 exhibit a capacity for casting off the leaves during seasons of 

 drought, more or less irrespective of the time of the year, while 

 some interesting features of the formation and casting away of the 

 bark have been noticed. 



All of the species bear strong spines and seem to be included 

 under the single colloquial name "ocotillo" by the Mexicans, 

 who use the living plants for hedges and sometimes erect barriers 

 by thrusting the ends of heavy branches into the ground in rows. 

 Messrs. Coville and MacDougal report having seen shrubs of 

 Fouquieria splendens planted within a few inches of young shade 

 trees in the streets of Alamogordo, New Mexico. The spreading 

 spiny branches were held in a cylindrical clump around the trunk 

 of the tree by means of wire and formed a most effective pro- 

 tection against damage by animals. 



During the course of some recent work upon this genus, Mr, 

 G. V. Nash called my attention to the unusual manner in which the 

 spines were formed, which he described as " developed within the 

 petioles of the leaves on the new growth, becoming apparent when 

 these fall." t The general anatomical facts presented seemed of 

 sufficient interest to warrant a detailed examination, and the results 

 of my observations upon Fouquieria splendeus and F. Macdougalii, 

 specimens of which are growing in the conservatories of the New 

 York Botanical Garden, are presented below. 



* The results described in the following paper were obtained by the aid of a Re- 

 search Scholarship in the New York Botanical Ciarden, in 1903. 



fNash, G. V. A revision of the family Fouquieriaceae. Bull. Torrey Club, 30 : 

 449. 1903. 



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