302 



HUTCHINSON'S POPULAR BOTANY 



the prickly to the unarmed forms of leaves in the plant named are so 

 numerous and marked, that the species has been separated into varieties 

 to distinguish them. Compare, for example, a leaf of Henderson's Holly 

 (Ilex a. hendersoni) with one of the Doningfcon variety (Ilex a. donington- 

 ensis), and both with a leaf of the Hedgehog Holly (Ilex a. ferox, fig. 362) ; 

 which latter has prickles not only at the margin, but also on the upper 

 surface. Its popular name is, indeed, exceedingly appropriate ; so, too, is 



its Latin appellative /mw, 

 " savage. ' Several plants of 

 the large genus Solanum, to 

 which the Potato-plant and 

 Woody Nightshade belong 

 (e.g. S. fontanesianum, jac- 

 quinij and maroniense}, have 

 spiny erections on both sides 

 of the leaf. They are borne 

 upon the midrib and veins, 

 and make the plants ex- 

 tremely awkward things to 

 handle. 



Many other protective 

 arrangements more or less 

 similar to those described 

 occur readily to the mind ; 

 as, for instance, the sharp, 

 strong, needle-shaped (acicu- 

 lar) leaves of many Grasses ; 

 the formidable thorny ter- 

 minations of the leaves of 

 the Agaves, and the spine- 

 bordered lobes of leaves like 

 the Thistle (Carduus), Teasel 

 (Dipsacus), and Acanthus. It 

 has been asserted that in 

 the- Southern Alps sheep will 

 frequently return from pasture with their nostrils cut and bleeding, and 

 the shepherds know at once that the cause of the mischief is a species 

 of stiff-leaved Grass, Festuca alpestris, which they seek to destroy by burn- 

 ing. In some instances, Grasses which cause discomfort to grazing animals 

 will be dealt with by the animals themselves, who seize them low down 

 with their teeth and tear them from the ground. Kerner saw thousands 

 of tufts of the Mat-grass (Nardus stricta), which had been rooted up by 

 oxen, lying dried and bleached by the sun on some meadows in the 

 Tyrolese Stubaithal. 



FIG. 369. BRISTLE-GALL ON OAK. 

 These galls are caused by the gall-wasp, Andricus lu 



[7. Holmes. 



