Quercus virens, manner of germination, 85, 557

R.

Radiation at night, effect of, on leaves, 284-286

Radicles, manner in which they penetrate the ground, 69-77; circumnutation of 69; experiments with split sticks, 74; with wooden pincers, 75; sensitiveness of apex to contact and other irritants, 129; of Vicia faba, 132-158; various experiments, 135-140; summary of results, 143-151; power of an irritant on, compared with geotropism, 151-154; sensitiveness of tip to moist air, 180; with greased tips, 185; effect of killing or injuring the primary radicle, 187-191; curvature of, 193; affected by moisture, 198; tip alone sensitive to geotropism, 540; protrusion and circumnutation in a germinating seed, 548; tip highly sensitive, 550; the tip acts like the brain of one of the lower animals, 573 —­, secondary, sensitiveness of the tips in the bean, 154; become vertically geotropic, 186-191

Ramey on the movements of the cotyledons of Mimosa pudica, and Clianthus
Dampieri at night, 297

Ranunculus Ficaria, mode of breaking through the ground, 86, 90 —­, single cotyledon, 96 —­, effect of lateral light, 484

Raphanus sativa, sensitiveness of apex of radicle, 171
—­, sleep of cotyledons, 301

Rattan, Mr., on the germination of the seeds of Megarrhiza Californica, 82

Relation between circumnutation and heliotropism, 435

Reseda odorata, hypocotyl of seedling slightly heliotropic, 454

Reversion, due to mutilation, 190
Rhipsalis cassytha, rudimentary cotyledons, 97

Ricinus Borboniensis, circumnutation of arched hypocotyl, 53

Robinia, effect of bright sunshine on its leaves, 445
—­ pseudo-acacia, leaflets vertical at night, 355

Rodier, M., on the movements of Ceratophyllum demersum, 211

Royer, Ch., on the sleep-movements of plants, 281, n.; on the sleep of leaves, 318; the leaves of Medicago maculata, 345; on Wistaria Sinensis, 354

Rubus idaeus (hybrid) circumnutation of stem, 205
—­, apogeotropic movement of stem, 498

Ruiz and Pavon, on Porlieria hygrometrica, 336

S.

Sachs on “revolving nutation,” 1; intimate connection between turgescence and growth, 2, n.; cotyledon of the onion, 59; adaptation of root-hairs, 69; the movement of the radicle, 70, 72, 73; movement in the hypocotyls of the bean, etc., 91; sensitiveness of radicles, 131, 145, 198; sensitiveness of the primary radicle in the bean, 155; in the common pea, 156; effect of moist air, 180; of killing or injuring the primary radicle, 186, 187; circumnutation of flower-stems, 225; epinasty, 268; movements of leaflets of Trifolium incarnatum, 350; action of light in modifying the periodic movements of leaves, 418; on geotropism and heliotropism, 436, n.; on Tropaeolum majus, 453; [page 589]

SARRACENIA—­STAPELIA