INDEX. 



6I 5 



Plane-tree family, 443. 

 Planes, seedling varieties of, 444. 

 Plant improvement, aids to, 10 ; improve- 

 ment, how most desirable, 16. 

 Planters' Table, 596. 

 Planting, table of right distances, 597. 

 Plants, careful selection of, for seed- 

 bearing, 14; dioecious and monoecious, 

 for hybridising, 15; hermaphrodite, 15; 

 improvements in cultivated, 9 ; insect- 

 fertilised, 140 ; life of, 7 ; night-bloom- 

 ing, 88; nutrition of, 12; per acre or 

 rod, how to cultivate, 596 ; per post, 

 41 ; review of cultivated, 168 ; succu- 

 lent, how to increase, 48 ; wind-fertil- 

 ised, 138. 

 Platanacese, 443. 



Plum, Magnum Bonum, sport of, 99. 

 Plumbago family, 444. 

 Plums, late-keeping, 477; seedling varieties 



of, 480 ; types of, stocks for, &c., 476. 

 Poinsettia, 306. 

 Polemoniacese, 445. 

 Pollen, 106. 



(A paper " On Pollen," by M. P. Edge- 

 worth, was read at the Linnean 

 Society's meeting, March 2, 1876. 

 The author treats of the shape 

 and relative size of the pollen- 

 grains in many orders of plants. 

 About 400 different species have 

 been investigated by him each mea- 

 sured to scale, and sketched accor- 

 dingly. Some families of plants, 

 he finds, present great uniformity 

 of figure and size in their pol- 

 len ; but, on the contrary, others 

 are as notable for diversity, even in 

 what would seem closely - related 

 species. In the ' Gardeners' Chron- 

 icle' (1876) Mr W. G. Smith gives 

 careful sketches of about 100 sorts 

 of pollen, the results of his observa- 

 tions being much the same as those 

 obtained by Mr Edge worth.) 

 Pollen, action of, foreign references to 

 writers on, 104; and insects, 106; appli- 

 cation of the, in; application of, to the 

 stigma, in, 113; application of, 129; 

 facilitating the growth of, 114; growth of, 

 fertilising-tubes of, 113; growth of, in 

 nectar, 196; how obtainable, 42; how 

 to preserve, no; immediate effects of 

 foreign, 102; insect-carried, 143; irregu- 

 larity of, not a test of hybridism, 96; 

 keeping properties of, 50; masses (see 

 Pollinia), 143; mixed, 127; natural pro- 

 tection of, 107 ; of a Clematis, 109 ; of a 

 Rhododendron, 109; of Lilies, Azaleas, 

 Ceratozamia, Caladium, Date - palm, 

 &c., no; of Jatropha, 109; of Willows, 

 109; per post, 42; potency of common 

 Cabbage, 211; preservation of, 106, 109, 

 151; prepotence of foreign, 89; prepo- 

 tence of foreign, in Passiflora, in; quan- 

 tity requisite, 116; variability of, in- 

 duced by culture, 96 ; varieties of, 106; 

 waxy, of Orchids and Asclepiads, 113; 

 wind-wafted, 138; tubes, growth of, 115. 

 (The extremely thin tubes emitted by 

 pollen-grains commence to grow in 

 about thirty minutes after they are 



placed in Hoya nectar or Agave 

 mucus on a strip of thin glass or 

 microscopic slide, and they continue 

 growing rapidly until the nectar 

 dries up. These tubes are trans- 

 parent, and a current or circulation 

 of their contents is plainly visible 

 under a moderately powerful glass.) 

 Pollen-tubes of Tigridia, 113. 

 Pollinia the pollen of such Orchids and 

 Asclepiads as is glutinous or adherent 

 in wax-like masses, 143. 

 Polygoniaceae, 447, 

 Pomaceous family, 457. 

 Pondweed family, 358. 

 Poplar family, 523. 

 Poplars, increase of, 581. 

 Poppy family, 427. 

 Porcher on Fuchsia hybrids, &c. , 400 ; on 



hybrid and seedling Magnolias, 391. 

 Portulacacese, 447. 

 Potato family, 538; grafting, 547; seed of, 



546- 



Potatoes changed by grafting, 61. 

 Prepotence, 120; male, Herbert on, 121; 

 of male and female parents, Lindley on, 

 170; of pollen -parents in Zonal Pelar- 

 goniums, 323; preservation of pollen, 106. 

 Primrose family, 448. 

 Primroses, 451. 



Primula, 451 ; Chinese, seed-sowing, &c , 

 587 ; seed treatment of, 455 ; elatior, 98 ; 

 hybrid, Darwin on, 7 ; wild hybrids of, 7. 

 Primulacese, 448. 

 Primulas, wild hybrid, 452. 

 Propagating-houses, 17; houses for hardy 

 plants, 17; pits, 17; pits, arrangement 

 of, 1 8. 



Propagation, artificial modes of, 43; by 

 cuttings, 47; nature's main plan of, 6; 

 vegetative, 43. 

 Propagator's Calendar for each month of 



the year, 579. 



Proportionate results of cross-breeding, 94. 

 Protandrous flowers, 116. 

 Proteacese, 457. 

 Protean family, 457. 

 Protogynous flowers, 11. 

 Protogyny in Calceolaria, 531. 

 Prunus (Plums), 475. 

 Psidium or "Guavas," 400. 

 Purslane family, 447. 

 Pyracantha on Hawthorn stock, 60. 

 Pyrus (classically, Pirus), 481; Aitcuparia, 

 graft variegation in, 62. 



QUERCUS, 271. 



Quetier on hybridising the Radish, 211 ; 



on Radish and Cabbage hybrids, 211. 

 Quince, 469 ; stocks for, &c., 471 ; stocks 



for Pears, 484 ; stocks for Pyracantha, 



60. 



RACES, permanence of, or fixation of, 125. 

 Radish, hybridism of, 211 ; races of, 211. 

 Ranunculus, 519; hybrids of, 520; in- 

 crease of, 581. 

 Raphanus, hybrids of, 211. 

 Raspberry, the, 504. 

 " Rat's-tail" Cereus, 219. 

 Reciprocal hybrids, 154. 

 Reciprocity of scion and stock, 63. 



