STANDLEY TREES AND SHRUBS OF MEXICO. 941 



toothpicks, and in some of tiie missions of California tliey employed tliem for 

 knitting stockings, straiglitening out tlie tips and reducing tlie tliicker part. 

 Among tiiese spines tlie viznaga produces its handsome flowers, tinged with 

 white, red, and yellow, which are followed by the fruit, much smaller than 

 that of the tammid, and full, like that of the cardon, with viscous juice and 

 seeds, which latter the Californians eat, after preparing them like those of the 

 carddn. In Mexico tliey make a good sweetmeat from the juicy pulp 

 of the viznaga." Clavigero also makes the following shrewd statement, which 

 indicates that he had no mean knowledge of plants : " It is certainly wonder- 

 ful that the plants of which I have spoken, and others of which I shall speak 

 later, have more juice in arid places than other kinds of trees have in humid 

 regions ; but it is still more remarkable that they maintain themselves with- 

 out any deterioration with little or no dew, although it may not rain for 10 

 months or more, as often happens in California. I believe that these plants are 

 more juicy because they transpire less, inasmuch as they have no leaves, for 

 these, as is the fundamental belief of physicists, are the principal organs of 

 tranpiration among plants: it may be conjectured that the Creator denied 

 these plants leaves because He destined them to inhabit dry lands." 



Plants very large, often 1 meter high or more (except apparently nos. 2, 4, 

 and 5). 

 Areoles with a marginal row of bristles or hairs. 

 Areoles with weak marginal hairs. 



Central spines yellowish; flowers yellow 1. F. stainesii. 



Central spines bright red; flowers red 2. P. pringlei. 



Areoles with marginal bristles. 

 Central spines hooked. 



Central spines up to 12 cm. long and 8 mm. wide 7. F. horridus. 



Central spines 8 cm. long or less, 4 to 6 mm. wide. 

 Inner perianth segments pink. 



Inner perianth segments linear 3. F. fordii. 



Inner perianth segments oblong 4. F. townsendianus. 



Innner perianth segments yellow to red, the outer pinkish. 

 Inner perianth segments about 2 cm. long; spines yellow to red. 



5. F. chrysacanthus. 

 Inner perianth segments 4 to 5 cm. long ; spines white to reddish. 



6. F. wislizeni. 

 Central spines straight or more or iess curved but not hooked. 

 Central spines flexible, thin. 



Central spines more or less appressed; seeds less than 2 mm. long. 



8. F. lecontei. 

 Central spines more or less tortuous and spreading; seeds more 



than 3 mm. long Q. F. acanthodes. 



Central spines dagger-like, straight, erect 10. F. santa-maria. 



Areoles without marginal hairs or bristles. 



Spines all alike 11. F. diguetii. 



Spines unlike, the radials different from the central. 

 Central spines more or less hooked. 



Central spine one 12. F. covillei. 



Central spines 4 1 13. F. peninsulae. 



Central spines not hooked. 

 Flowers lemon-yellow; inner perianth segments elongate. 



14. F. rectispinus. 



Flowers crimson; perianth segments all short 15. F. orcuttii. 



79G88— 24 7 



