Part 197

Orchids, 151.

Orchis, 276, 331, 332, 333.

Oreobolus, 285.

Oreodoxa, 301.

Organs of attachment, 4.

Origanum, 536, 539, 541.

Ornithogalum, 312, 314.

Ornithopus, 466, 472.

Orobanche, 334, 528, 529.

Orontieæ, 303.

Orontium, 304.

Orris-root, 321.

Orseille, 142.

Orthoploceæ, 400.

Orthospermeæ, 493.

Orthothecium, 197.

Orthotrichum, 197.

Orthotropous, 242, 243.

Oryza, 293.

Oryzeæ, 293.

Oscillaria, 10, 23, 24, 26, 37.

Oscillariaceæ, 24.

Osiers, 152.

Osmunda, 209, 215.

Osmundaceæ, 202, 210, 215.

Ostioles, 73.

Ostropa, 133.

Ostropaceæ, 133.