270 
Humidity, methods of controlling, 193. 
Hybrids and crosses defined, 19. 
Hydrocyanic gas, 156. 
Hydrogen, source of in plants, 42. 
Hypocoty] defined, 31; develops differ- 
ently in different species, 35; roots 
start from, 33; seeds in which it 
lengtbens must be planted shallow, 
35. 
Ice often destroys low plants, 118. 
Immature vs. ripe seeds, 101. 
Imperfect flowers, 97. 
Implements for pruning, 246; for trans- 
planting, 227, 228, 229. 
Improvement possible through plant 
variability, 250. 
Individuals defined, 17. 
Injury by cold, methods of averting, 
119. 
Insecticides, 151; apparatus for apply- 
ing, 158; use of, 158. 
Insects, beneficial, 149, burrowing, 160, 
161; destroying by poisons or caustics, 
151; eating, 159; hand-picking, 150; 
injurious, life history of 164; leaf- 
eating, 159, 160; ravages, method of 
preventing, 149; repelling, by means 
of offensive odors, 150; root-eating, 
159, 160; sucking, 159, 163. 
Insects, trapping, 150. 
Internodes defined, 76; stem lengthens 
by elongation of, 77; ultimate length 
of, 78. 
Iron essential to formation of chloro- 
phyll, 43. 
Irrigation, 133. 
Kainit, 145. 
Kerosene applied with water, 155; as 
an insecticide, 154. 
Kerosene emulsion, formulas for, 154, 
155. 
Killing trees by girdling, 59. 
Knife, budding, 216; grafting, 208; prun- 
ing, 246. 
Knowledge, application of essential to 
success, 10, 
Latb screen for shading young plants, 
134. 
Principles of Plant Culture. 
Leat-buds, 84; comparative vigor of, 85. 
Leaf cuttings, propagation by, 201. 
Leaf development, importance of, 79. 
Leaf fall, time of, an index of wood 
maturity, 106. 
Leaf eating insects, 159, 160. 
Leaf-miners, 162. 
Leaves, 78; are usually short-lived, 81; 
comparative size of, 80; function of, 
78; manurial value of, 81. 
Leguminous plants enrich the soil with 
nitrogen, 144. 
Lenticels, 48. 
Lever shears, 248. 
Life, culture deals with, 12. 
Life, what is it? 12° 
Lifting large trees, 220. 
Lifting the plant, directions for, 219. 
Light does not hinder germination, 31. 
Light, unfavorable, how affecting the 
plant, 134. 
Living beings, cellular structure of, 13. 
Localities most subject to untimely 
frosts, 125, 
Locusts, 157. 
London purple, 152. 
Low plants often destroyed by ice, 118. 
Magnesium, part played by, in plant, 43. 
Mallet cuttings, 195. 
Manure increases water-holding capac- 
ity of soil, 43. 
Manurial value of leaves, 81. 
Maturative pruning, 246. 
Maturity of plants, influence of drought 
on, 1382. 
Maximum defined, 24. 
Melons, tcreen-covered frame for pro- 
tecting hills of, 150. 
Mice, damage from, 148. 
Minimum defined, 24. 
Moisture, an enemy to stored seeds, 102, 
essential to germination, 24; excess- 
ive, causing cracks in fruits and veg- 
etables, 130; excites root growth, 62; 
excessive in air, injurious to plants, 
131; insufficient in air, causing exces- 
sive transpiration, 131; insufticient in 
soil, retards growth, 132. 
