INDEX AND GLOSSARY 



567 





" Mutations," deviations from type, 

 which have not been referred 

 directly to known causes, 471 ; 

 beneficial, preserved by Mendelian 

 segregation, 477 : origin of, 472, 



477- 

 Mutualism, a living together of two 



organisms with joint physiological 



action, 188. 

 Mycelium, an aggregate of fungal 



hyphae, 404 ; of Mucor, 423. 

 Mycoidea parasitica, 403. 

 Mycorhiza, the coalition of fungal 



filaments with the living tissues 



of other organisms, 194 ; initiative 



by fungus, 203. 

 Myosurus, hypogynous flower of, 



237 (Fig. 185) ; embryo-sac and 



endosperm of, 279 (Fig. 221). 

 Myrrhis, 525. 

 Myrsiphjdlum, dextrorse twiningstem, 



182 (Fig. 135) 



Narcissus, stoma of, 65 (Figs. 47, 48), 

 90 (Fig. 67), 99 ; chemotropic 

 pollen-tubes, 268 (Fig. 213, B) ; 

 flower of, 495, 496. 



Natural Families, 492, Appendix A. 



Needles of Pine, 303. 



Nemalion, 388 (Fig. 327). 



Neottia (Bird's Nest Orchis), mycor- 

 hiza in, 197 ; 202 (Figs. 153, 154). 



Nepenthes, pitches of, 207, 208 (Fig. 

 158). 



Nephrodium, leaf of, 327 (Fig. 266) ; 

 stock of, 328 (Fig. 267) ; sorus of, 

 337 (Fig. 278) ; sporangium of, 

 337 (Figs. 279-281) ; prothallus 

 of, 340 (Figs. 282-;284) ; apospory 

 and apogamy in, 352 (Fig. 295). 



Nephrodium pseudo-mas, v. poly- 

 dactylum, 478. 



Nettle, host for Puccinia caricis, 445. 



Neutral generation, dominant on land, 

 491. 



New Zealand flax, quahties of fibres 

 of, 146; leaf structure, 155 (Fig. 

 115, A), 156. 



Nightshade (Atropa), 5 28. 



Nitrifying Bacteria, 105, 107. 



Nitrogen, supply of, 105, 204, 207 ; 

 combined, 106. 



Nolina, qualities of fibres, 146. 



Non-septate sac, as mode of con- 

 struction, 139 (Fig. 98). 



Nostoc, 457. 



Nucellus, the body of tissue forming 

 the centre of an ovule, and enclos- 

 ing the embryo-sac : the mega- 

 sporangium ; 258 (Figs. 206, 207). 



Nuclear membrane, 464 (Fig. 392) , 466. 



Nuclear pairing in Phragmidium, 

 ^447 (Fig. 384)- 



Nuclear sap, 464, 466. 



Nuclear spindle, 465 (Fig. 392) ; 

 bipolar, 468. 



Nucleolus, a highly refractive body, 

 probably of reserve substance, in 

 the nucleus : 464, 466. 



Nucleus, a definite spherical or oval 

 body, reproduced by division, 

 which acts as centre of the activity 

 of the cell : 18 (Fig. 9) ; its im- 

 portance in syngamy or fertilisa- 

 tion, 470 ; somatic division of, 

 464 (Fig. 393) ; tetrad division of, 

 467 (Fig. 393). 



Nutrition, Chap. vii. 98. 



Nutritive jacket, a layer of nutritive 

 tissue surrounding the embr^'o- 

 sac in Gamopetals : 280 (Fig. 222). 



Nymphaea, floating leaves of, 178. 



Oak, attacked b}^ rhizomorphs of 

 Armillaria, 203. 



Oat, analysis of, 547 ; origin of, 548. 



Odontoglossum, mycorhizic infection 

 of, 200 (Fig 151). 



Oedogonium, 392, 393 (Fig. 331). 



Ofl'als, 547. 



Oidium-condition, of ^Mucor, 426. 



Onion, bulbils of, 213 ; origin and 

 analysis of, 541. 



Onoclea, fertilisation of, 345 (Figs. 

 286, 287). 



Onygena, sporadic occurrence of, 40S. 



Oogonium, the organ in Algae and 

 Fungi, which contains one or more 

 female gametes, or ova : of Fucus, 

 383 (Fig. 325) ; of Oedogonium, 

 393 (Fig. 331) ; of Vaucheria. 

 397 (Figs. 335, 336) ; of Oomycetes 

 410, 420, 422 (Fig. 357) ; of 

 Pythium, 409 (Fig. 344), 416. 



Oomycetes, 410, 412, 413. 



Oospore, of Pythium, 41O. 



Oosporeae, aquatic origin of, 454. 



Open bundle, one possessing active 

 cambium, 46. 



Operculum, the lid which falls away 

 from the ripe capsule in Mosses, 

 362 (Fig. 305). 



