5 62 



BOTANY OF THE LIVING PLANT 



Herbaceous Dicotyledons, stem of, 35. 



Hereditary transmission, a conse- 

 quence of sex, 462. 



Heredity, 461 (Chap. xxxi.). 



Hermaphrodite, where male and 

 female organs are on the same 

 individual : applied to flowers 

 when they contain both stamens 

 and carpels, 222, 265. 



Heterocysts. of certain Cyanophyceae, 



457- 



Heteroecism, where the life-cycle 

 of a parasite is completed by 

 stages on distinct hosts, 422. 



Heterosporous, applied to vascular 

 plants in which there are distinct 

 megaspores and microspores, 325, 

 351 ; a derivative state, 486 ; 

 adoption by Pteridophytes and 

 seed-plants, 489. 



Heterothallic, in Mucorini, where 

 zygospores are only produced on 

 meeting of branches of two differ- 

 ent mycelia, 426 (Fig. 361). 



Heterotrophic, applied to nutrition 

 by some accessory or irregular 

 method, in addition to, or even 

 superseding self-nutrition, 187 

 (Chap. xi.). 



Heterotype division, another name i 

 for Reduction-division : conveying ' 

 the fact that the resulting nuclei 

 are of a type different from their 

 predecessors, 468, 469. 



Heterozygote, formed by union of 

 two dissimilar gametes, 475, 476. 



Hieracium, somatic parthenogenesis 



in. 477- 



Hilum, scar of attachment of a seed 

 to the parent plant : 6. 



Himanthalia, 385. 



Hip, of Rose, a succulent hollow 

 receptacle, 293. 



Hippuris, Mare's tail, 16, 17 (Figs, i 

 7, 8), 36, 40. 



Hofmann's apparatus, 103 (Fig. 76). | 



Holly, indurated leaf-margin of, 158. : 



Homologous alternation, 479, 481. 



Homoplastic development, 160. 



Homoplasy, where similar morpho- 

 logical results are produced by 

 adaptation in two or more distinct 

 evolutionary lines : of parasites, 

 193 ; in Algae, 401. 



Homosporous, applied to archegoni- 

 ate plants in which there is only 

 one type of spore, 325, 351 ; a 



primitive state, 485, 487 ; fully 



exploited in Pteridophytes, 489. 

 Homothallic, in Mucorini, where 



zygospores are produced on meet- 

 ing of two branches of the same 



mycelium, 426. 



Homotype-division, the second divi- 

 sion in the spore-tetrad, carried 



out like any somatic division. 



466, 469. 

 Homozygote, formed by union of 



two gametes similar in respect of a 



given character, or characters, 



475 (Fig. 396). 

 " Honey "Dew," 406 (Fig. 341) ; 436 



(Fig. 369). 

 Honey Agaric, parasitism of, 404 



(Fig. 340); 411 (Fig. 347). 

 Hooks, in seed dispersal, 292 (Fig. 



238). 



Hop, twining stem of, 182. 

 Hop-mildew (Sphaerotheca) , 431. 

 Hordeum (Barley) analysis of, 547 ; 



origin of, 548. 

 Horse-chestnut (Aesculus) , 1 3 (Fig. 6) ; 



69 (Fig. 52): 

 Horse-tail, vegetative propagation of, 



218, 316. 

 Host, a plant or animal that supplies 



food to a parasite, 187. 

 Hottonia, 101. 

 Humble-bee, agent for pollination of 



Aconite, 266. 



Humus, leaf-mould, decaying vege- 

 table matter of the soil, 188. 

 Hura (Sand-box Tree) , explosive fruit 



of, 133 (Fig. 94) ; dehiscence of 



fruit, 287, 516. 

 Hyacinth, qualities of fibres of, 1 46 ; 



perennation of, 165 (Fig. 125). 

 Hybridisation, the result of crossing 



of more or less dissimilar parents, 



470. 

 Hydrom, water-conducting tissue of 



Mosses, 357 (Fig. 299). 370. 

 Hydrophytes, plants adapted to life 



in presence of plentiful water, 175, 



178. 

 Hydrotropism, response to stimulus 



of unequal water-supply, 128 ; 



positive, of pollen-tubes, 268. 

 Hygroscopic movements, due to 



changes in degree of moisture, 



133 (Figs. 93, 94, 95) ; of seeds and 



fruits, 297. 

 Hymenial gonidia, Algal cells in the 



hymenium of a Lichen, 440. 





