156 APPENDIX II 



CHAPTER X 



PROTECTION 

 General Reading 



Kerner and Oliver, Volume I, Part 2, pp. 430-451. 



Hardinge, With the Wild Flowers, pp. 217-258 (Poisonous 

 Species) . 



Gray, Text-book, pp. 55 ( 112, 113), 117 ( 227 a) ; Ele- 

 ments, pp. 41 ( 101, 102), 64 ( 167). 



Croupin, The Thorns of Plants (Popular Science Monthly, 

 Volume 46, pp. 498-501 (with figures), 1895). 



I. The Orange, Lemon, or any of the Cratcegus sp., 

 i.e. Scarlet Thorn, Hawthorn, or Cockspur Thorn, are ex- 

 cellent. Leafless branches may be dried and soaked out 

 again as recommended under Chapter VIII. 



II. In the Eastern Barberry (Herberts vulgaris}, after 

 the leaves have appeared in the spring, a complete series of 

 gradations from leaves to spines may be traced in many 

 instances. Read Gray, Elements or Text-book, referred to 

 above. 



III. The long, slender, upright shoots from the base of 

 Robinia Pseudacacia show these spines beautifully. The 

 Acacia armata or Spiny Acacia is fairly commonly grown 

 in California and to some extent in the greenhouses East. 

 The stems of the Euphorbia splendens, common in green- 

 houses all over the country, is also armed with spines occupy- 

 ing the places of stipules. The spines in Xanthium spinosum, 

 a frequent weed in California, are also stipular. 



