IXDKX 



4S1 



Rhubarb, protection of root of, 16"J. 

 Ribes. See Currant. 

 Ricinus. See Castor-bean. 

 Riley on food of plant, 344. 

 Rind, function of. 2:)7. 



of root, 120.* 121. 



of stem, 224,* 225,* 232,* 2;(:;, :i3U,* 



starch in, 258, 

 Ring, annual, 247. 



bast-226, 246. 



cambium— 24G. 



woody, 226, 246. 

 Ringing, 256, 2.57, 3lN. 

 Ripening of fruits, 31G. 



— seeds, 314. 

 River water, plant-food in, 1 i^, 

 Rivers, self-purification of, ;J82, 383. 

 Roberts, on fertilizers, 153. 

 Robinia. See Locust. 

 Rocks, decomposition of, 109, 144, 145. 

 Roguing, 451. 

 Rogues, 451 

 Rolling of leaf protects it against dryiuK. 



213, 334. 

 Root, aeration of, 36, 37,* 38, 39,* 40, 103, 

 119,* 120,* 124-126, 128, 130, 132. 



aerial, 275 * 



absorption of water by. 88. 102, 103, 119,* 

 120,* 121-123 * 



affected by heat, 332. 



salts, 124. ;!30. 



acid excreted by. 141-143.* 144, 145. 



anchors plant in soil, 87.* 



behavior of, to obstacles, 99.* 



buds formed on. 249. 



care of, 135, 136. 



climbing, 275.* 



contraction of, S7. 



decomposes rocks, 144. 145. 



depth of penetration of, 134, 135. 



direction of growth of, influenced by air, 

 89. 98, 135. 



centrifugal force, !:)2,y:;.* 



94. 



— food, 89. 98. 



gravity, 88,* 89,* 90, 91.* 



92. 93,* 94, 95, 98.* 99. 



heat, 89, 98. 



-= ^ water, 89, 95,* 96,* 97, DS 



EE 



Root, effect of heat on, 33:^. 



water on the form of, ;j41. 



etches marble and plaster of Paris, 1 J4. 



excretion by, 141-143* 144. 145. 



exploration of soil by. 133-135. 



food in, 122, 125. 260. 



force of growth of, 81, 82,* 83, wi.* 85. 



fungi on. 150. 



gives off carbonic acid, 141-143. *Ji4. 



growing region of. 85,* 86. 



microscopic structure of, 120.* 121, 255. 



needs air, 125. 



of water-plants, 339. 



osmotic action of, 123, 124- 



path of water in, 120.* 121. 



penetration of soil by, so,* si. "^ 



propagation by, 433. 



protection of, 161, 162. 



proteids in. 255. 



pruning of, 136, :;18. 



regeneration of, 86. 



resemblance of rhizome to, 277. 



selective action of, 161. 



shallow vs. deep, 87. 



storage of food in 260. 



strengthening fibers of, 120,* 207. 2()8. 



sugar in, 122. 



tip of, how protected, 86. 



result of injury to, 86. 



treatment of, to promote fruit produc- 

 tion, 342. 



tubercles of, 49,* 384, 385. 

 Root cap, 86. 



Root-hairs, absorb water by osmosis, 121- 

 123,* 124, 242. 



effect of water on growth of, 102. 



method of obtaining, 100,* 101.* 



of radish, 100,* 101.* 



of Wandering Jew, 102.* 



relation to soil-particles, 119, 120, 121. 



turgidity of, 123. 

 Root-pressure, 243,* 244, 

 Root-stock. See Rhizome. 

 Rosa. See Rose. 

 Rose, calyx of, 288. 



climbing of, 270. 



protection of, against animals, 221. 

 Rose, Moss, origin of, by bud variation, 420. 

 Rose, family, cross-pollination of, 393. 



