GLOSSARY 259 
Obtuse : Blunt, not pointed. 
Ochrea : A membranous stipule which surrounds the stem. 
Odontophore : The “ tongue ” of certain molluscs. 
Oldhamia : A Cambrian fossil. 
Oligocene : The second of the five periods of the Cainozoic Era. 
Orbicular : Nearly round and flat. 
Ordovician : The second of the six periods of the Paleozoic Era. 
Ornithology : The study of birds. 
Outerop : The edge of tilted strata as it appears on the surface. 
Ovary : The young seed-vessel. 
Ovate : Egg-shaped. 
Oviparous : Bringing forth eggs. 
Ovules : Immature seeds. 
Paleontology : The science of ancient life, the study of fossils. 
Paleeozoic : The second of the four great geological eras. 
Palmate : Having lobes spreading out from a centre, like the 
fingers of the hand. 
Pappus : The hairy or downy crests of the fruits of composite 
plants. Example, dandelion “ clock.” 
Parasite: A plant or animal living at the expense of another 
plant or animal. 
Pariasaurus : An extinct reptile. 
Paripinnate : A leaf with an equal number of distinct leaflets on 
either side of the stalk, all leaflets being opposite. 
Pedicels : Branches of a common flower-stalk or peduncle, each 
branch bearing a flower. 
Peltate : A leaf which has its stalk attached to its surface, not 
to its margin or base. 
Pendulous : hanging, attached in a hanging fashion. 
Perfoliate : When the stem seems to pass right through the blade 
of the leaf. 
Perianth : The outer envelope of a flower in which calyx or 
corolla cannot be distinguished. 
Pericarp : The outside or rind of fruits. 
Permian : The last of the six periods of the great Paleozoic 
Era. 
Petals : The usually coloured leaves of the corolla. 
Petiole : The leaf-stalk. 
Pinnatifid : Leaf cut deeply into segments reaching nearly to 
the midrib. 
Pistil : The female organ of a flower. The pistil includes the 
ovary, style, and stigma. 
Peat : Compressed and altered vegetation, which can be used for 
uel. ° 
Petaloidee : A sub-class of monocotyledonous plants whose 
flowers have petals. 
