592 THE GARDENER’ ASSISTANT. 
Bev ene a oo &c., descript. and cult., | 
1, 396; for thesubtropical garden (illust. i; 
1, 645. 
Nierembergia rivularis — descript. and 
cult., 1, 366. 
Nigella—species, &c., descript., cult., and 
illust., 1, 396. 
Night-soil—as manure, i, 158. 
Niphobolus—(see Polypodium). 
Nitrites and nitrates — formation of, i, 
134. 
Nitrogen— 
Ammonia formation—combination of nitro- 
gen and hydrogen, 1, 143. 
Assimilation of free nitrogen by plants— 
question of, i, 141, 142, 146. 
Increase of nitrogen formed during process 
of decay, &c., of certain vegetable 
products—table showing, 1, 138. 
Leaves of trees—table ee amount of 
nitrogen in, 1, 138; power of plants to 
absorb nitrogen by their leaves, 1, 144. 
Loss of nitrogen as nitric acid, &c., in 
drainage—table showing, 1, 133. 
Mushroom culture — supply of nitrogen 
essential to, 11, 463; analyses showing 
per cent of nitrogen in various dungs 
used, il, 464. 
Nitrogen as ammonia and _ nitric acid, in 
the rainfall of three years, &c.—table 
showing, 1, 142, 143. 
Nitrogen as nitrates in drainage water— 
table showing amounts, 1, 132. 
Nitrogen in soil—combinations of ammonia 
and other bases, i, 43. 
Organic matter and nitrogen in various | 
soils--table showing amounts Of, i, 150. 
Plant nutrition—importance of nitrogen, 
and effect of nitrogenous manures, 1, 
2, 43 oa 144; alr as a source of | 
food, 
Riera: sate Arnon of nitrogen as | 
nitric acid per acre in, 1, 133. 
Sources of the nitrogen of crops—humus | 
as a source, i, 136; combined nitrogen | 
in rain, &c., 1, 142; other sources of 
combined nitrogen, 1, 143-146. 
Sources of the nitrogen of vegetation—ques- 
tion of, 1, 141. 
Nodes and internode of stem—descript. 
of, 1, 38. 
Nolana—descript. and cult. of, i, 396. 
Nomenclature, system of—explanation | 
of principle of, i, 67. 
Non-alcoholic drinks, production of— 
use of fruit juices for, 11, 358. 
Nobar per ilam Carmichaelize—descript. | 
Of, 1, 310. 
MpEnGrilsoaa deceit and cult. of stove 
and greenhouse species, i, 597, of hardy 
species, i, 607. 
Nucellus of ovule— formation ofa ss: 
Nucleus—formation of (illust.), i, 27. 
Nuphar-—species, &c., pecrente of, i, 382. 
Nut-weevil—descript. and treatment, i, 77. 
Nuthatch —as a garden friend, i, 119. 
Nutrition of plants— 
Air as a source of food, i, 43. 
Bacteria or microbes—influence on, i, 43. 
Conditions of plant life, i, 41. 
Leaf functions, 1, 40, 41. 
Light, action of, 1, 44. 
Movement of liquids in plants, i, 44. 
Overfeeding—effect of, i, 63. 
Soil as a source of food, water, and air, i, 
41-43; Rothamsted experiments, 1, 42. 
Nuts— formation of, i, 56. (For special nut, 
see titles Chestnut, Hazel-nut, &c.) 
Nuttallia cerasiformis—descript. of, i, 
310. 
Nycterinia—descript. and cult. of, i, 396. 
Nymphza—cultural requirements, methods 
of planting, &c., i, 378—380; descript. 
of species, &c. (illusts.), i, 382, 383; 
illust. of Nymphza pond, 1, 380. 
Nyssa—species of, descript., i, 310. 
O ; 
Oak-trees—pruning (illust.), i, 253-255, 256; 
descript. of genus, species, &c., 1, 315. 
Oca—(see Oxalis crenata). 
Ocymum basilicum (illust.) and O. mini- 
Oe cult., and uses of, 
» 402, 403. 
OcaEs olens—(illust.), asa garden friend, 
i, 115- 
Odontoglossum—calendarial directions, i, 
2) 3, 5; 7) 8, F1, 13, 16, 19, native) habi- 
tats and cultural requirements, Oy SV 
561, 563; house for, construction and 
management, 1, 559, 560, 561, 562; 
species, &c.,descript., cult., and illusts., 
1, 578, 579- 
Cnothera—descript. and cult. of perennial 
species, &c., 1, 367, of annual species, 
&c., i, 396, of CE. biennis as a vege- 
table, x 519. 
Old Man’s Beard — descript. and cult. of 
climber, 1, 296, 556. 
Olea—species of, descript. and cult., 1, 539. 
Olearia—descript. and cult. of hardy orna- 
mental species (illust.), 1, 310, of green- 
house species (illust.), 1, 539, 540, of 
O. stellulata for forcing, i, 623. 
Oleaster—descript. of shrub, i, 300. 
Olive-tree—as greenhouse plant, descript. 
and cult., 1, 539. 
Omphalodes—descript. and cult. of peren- 
nial species, &c., 1, 367, of annual 
O. linifolia, 1, 397. 
Oncidium-—calendarial directions, i, 2, 5, 
10, 16, 18; species, &c., descript., cult., 
and illust., 1, 578, 580. 
| Onion fly-—descript. and remedies, i, 108. 
Onions— 
Autumn-sown—directions for sowing and 
subsequent cult., 11, 471. 
Calendarial directions, ii, 532 
541, 543, 546, 548, 550, 552; 
for forcing, 11, 537, 539, 542: 
Cottage-garden, &c., crops — methods of 
cult. me ll, 472. 
Crops onions may follow and be succeeded 
by, il, 390°. 
Descrot history, and extent of cult., ii, 
468. 
Egyptian onions—(illust.), cult. of, ii, 472. 
Forcing directions, 11, 472. 
Foreign names of, ii, 528. 
Gathering and storing the crop—directions 
and illust., 11, 469, 470, 566. 
Insect pests, &c.—list of, il, 474. 
Lists (illusts.) of vars. -- distinction and 
descript. of sorts, ii, 473-475; classified 
list of onions exhibited at vegetable 
conference, ll, 475. 
Offset onions — sowing, &c. directions, 
growth of ‘‘ scallions”, ii, 471. 
Packing, 11, 566. 
Pickling sorts—descript. and cult., 11, 470. 
Planting small bulbs of preceding year’s 
growth, li, 471. 
Potato onions—(illust.), cult. of, ii, 471, 472. 
Preserving—drying process, li, 356. 
Saving seeds—directions, 11, 472, 474. 
Seed quantities required for cropping, 11, 
391- 
Size of bulbs—effect of spring, autumn, 
&c., sowings, ii, 470. 
Soil and manures, ii, 468. 
Spring- sown — directions for sowing and 
after-treatment of plants, ii, 468, 469, 
for exhibition plants, il, 471. 
Oniscus asellus—descript. and treatment, 
1, 99. 
Onoclea—species, &c., descript. and cult., 
1, 607. 
Ononis arragonensis—descript. of, i, 310. 
Onosma—species, &c., descript., cult., and 
illust., i, 367. 
Onychium japonicum — as decorative 
ferns, i, 584. 
Oosphere—descript. of, i, 53. 
Oospore—descript. of, i, 53. 
Opuntia &c., descript. and cult., 
1, 620 
Orach—descript., uses, illust., and cult., ii, 
475, 476, 546; foreign names of, 11, 528. 
Orange scale—descript. and treatment, i, 
92. 
Oranges, Lemons, &c.— 
Citrus genus—descript. and origin, species 
used for horticultural purposes, ii, 310, 
Bilis 
Construction of house, beds, drainage, &c., 
ll, 311, 312; orchard- house, li, 274. 
General treatment—soil, manure, planting, 
il, 311; bottom- heat, temperature, ven- 
tilation, 11, 312, 313; pot cult., 11, 313; 
flowering and fruiting periods, Wy, Be) 2 
plants in bad health, un, 313, 314; shade, 
syringing, and water, il, 313, 315; prun- 
ing, training, 11, 313, 3t4i propagation, 
ll, 314. 
Illusts.—orange, 11, 311, oranges on 
wall in open air at Osborne, ii, 312, 
lemon, i, 313, lime, li, 314, shaddock, 
ll, 315. 
Insect pests, &c.—treatment of, 1, 313, 315. 
Lists of vars. ,descript. and illusts. —orchard- 
house, il, 274, oranges, ll, 315, lemons, 
limes, and pomalos, 11, 316. 
Orchard-house culture—vars. suitable, &c., 
li, 274, 275- 
Packing methods and form of packeaei used 
in colonies, il, 371. 
Preserving methods, il, 350. 
Orchard-house for Fruit Culture— 
Choice and form of trees suitable for, il, 275. 
Construction (illust. ) and temperature to 
suit various fruits, ll, 273, 274. 
General management— potting or planting- 
out trees, 11, 275; soil preparation, top- 
dressing mixture, il, 276; flowering 
period and fertilization of flowers, u, 
276; summer and autumn treatment, 
Nl, 276, 277. 
Illusts.—fruit-trees grown in orchard-house, 
il, 275, pear-tree in pot, il, 276, peach- 
tree in pot, il, 277. 
Insect pests, &c.—treatment of, ii, 278. 
Lists of fruit suitable for culture in, ii, 278. 
{For special fruit, see its name.] 
Orchards— 
Calendarial directions (see Calendar of 
Operations in the Fruit- and Kitchen- 
gardens). 
Commercial plantations of apples and pears 
(see titles Apples, &c., for Market, 
Pears for Market). 
Formation of new orchards—primary con- 
siderations, ii, 32; choice of site, 11, 32, 
33; soil suitable, preparation and im- 
provement of soil, ii, 33, 34; use of 
grass-land, ii, 34; manurial applica- 
tions, 11, 35. (See also sub-heading 
Plans. ) 
General management—treatment of ground 
in plantation, extent and protection of 
cultivated area around trees, li, 37, 38; 
catch-cropping, influence of, ii, 38, 39; 
manuring, general routine work, re- 
moval of trees for thinning purposes, 
li, 39. 
History of orchard establishment in British 
Isles, 11, 32. 
Improvement of old orchards—directions, 
il, 39. 
Plans (illusts.) for planting—Evesham or- 
chard, ii, 32; various systems, 11, 34-36; 
for mixed plantations, 11, 36, 37. 
Soil suitable—examples of chemical ae 
alysis of various soils, ii, 33, 34; 1 
provement measures, ii, 34. 
Spraying fruit-trees (see that title). 
Surplus and waste produce—utilization of 
(see Fruit-preserving). 
Orchid-houses— 
Arrangement of plants in, i, 566; foliage 
plants used for decorative purposes, 1, 
569- 
Calendarial directions for management of, 
i, 2, 3, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19+ 
pai 
