782 



ECOLOGY 



accumulation of food in 

 the affected tissues. In 

 some cases parasites cause 

 atrophy (reduced cell size) 

 or hypoplasy (reduced cell 

 number). Often gall tis- 

 sues remain in a condi- 

 tion more primitive than 

 that of uninfected tissues; 

 the primordia of wood and 

 bast, for example, often 

 remain parenchymatous 

 instead of developing into 

 complex tissues. 



The most astonishing 

 feature of galls is the de- 

 velopment of nutritive 



Figs. 1090— 1093. — Cross sec- 

 tions of galls, showing anatomical 

 features: 1090, a solid cynipid 

 gall from an oak twig, cut in 

 half; note the radiating lines of 

 tissue, and the central larval 

 chamber (c); 1091, a section of 

 an oak gall; e, epidermis; 0, 

 cortex, the grains representing 

 plastids (chloroplasts above and 

 leucoplasts with prominent starch 

 grains below) ; 5, protective layer 

 of sclcrenchymatous cells;/,/', 

 nutritive layers adjoining the 

 larval chamber, / being a layer 

 rich in starch, and /' a layer 

 whose cells are rich in proteins 

 and prominently nucleated; 1092, 

 part of the nutritive tissue of the 

 gall of Nematus gallorum; note 

 the resemblance to the tissues 

 in an intumescence; 1093, iso- 

 lated nutritive hairs of a Cepha- 

 loneon gall from a maple (Acer); 

 1091-1093, highly magnified. — 

 1090 after Kerner, 109 i after 

 Lacaze-Duthiebs, 1092, 1093 

 after KiJsiER, 



