376 



ESSEXTIALS OF BOTANY 



Plant society, 113. 



Plants, classes of, in relation to 



economy of water, 115-118*. 

 Plants, destruction of, by animals, 



122. 

 Plants of uneatable texture, 123. 

 Pleodorina, *298. 

 Pleurococcus, 212. 

 Plum hybrids, *319. 

 Plumule, *5, *14. 

 Pod, 183, 187, *194. 

 Poisonous plants, 125, 126. 

 Poisonous seeds, 21. 

 Poisons, plants containing, 125, 126. 

 Pollarded trees, 95. 

 Pollen, 162-169*. 

 Pollen, discharge of, *162. 

 Pollen grain, germination of, *165. 

 Pollen grains, *168. 

 Pollen grains, number of, per ovule, 



167. 

 Pollen, protection of, from visitors, 



173. 

 Pollen tubes, 163, 164, *165. 

 Pollen-carrying apparatus, 169, 



»170. 

 Pollination, 168-180*. 

 Polypetalous, 153. 

 Polysepalous, 153. 

 Pome, 188. 



Poplar, leafy twig of, *97. 

 Poplar twig, 51. 

 Potato tuber, 50, *60, 83, 84, 332, 



333. 

 Prickle, *123, *124. 

 Prickly leaves, *124. 

 Primary root, *14, 30. 

 Primrose, pollination in flowers of, 



*178. 

 Prooambium, *71. 



Propagation, by root, 42. 

 Protection of plants from animals, 



122-126*. 

 Proteids, 19, 20. 

 Proteids, tests for, 20. 

 Prothallium, *283, *284, *290. 

 Protonema, *274. 

 Protoplasm, *43, 44, 45. 

 Protoplasm, characteristics of, 44, 



45. 

 Psalliota, type study, 259-261*. 

 Pteridophytes, 280-294*. 

 Pteridophytes, remarks on, 293, 294. 

 Pucoinia, type study, 255-258*. 



Raceme, App. I, *357. 



Raspberry, *189. 



Ray, medullary, *70, *71, *72, *73, 



74. 

 Ray-flowers, App. I, *359. 

 Receptacle, 150, »156. 

 Red algffi, 234-237*. 

 Red clover, leaf of. *100. 

 Regular flowers, 149. 

 Reproduction in seed plants, 165- 



167*. 

 Respiration, 136, 140, 141. 

 Retuse, App. I, *356. 

 Rhachis, 282. 

 Rhizoids, hairs serving as roots 



in ferns, mosses, and liverworts, 



*265, «273. 

 Rhizopus, type study, 246-248. 

 Ring, annual, *73. 

 Ringent, *152. 



Rise of water in stems, 78-80. 

 Rookweed, type study, 230-233*. 

 Root, 30-42*. 



Root, adaptation to work, 41, 42. 

 Root, dicotyledonous, section, *37. 



