326 GLOSSARY 



Oval, in the shape of an ellipse, as in Fig. 6, p. 22. 



Ovate, with an outline like that of an egg, the broader end next the leaf- 

 insertion, as in Fig. 7, p. 23. 



Palaeontology, the stud}' of plants and animals in a fossil state, p. 36. 

 Palisade tissue, the close-celled tissue of the upper mesophyll, p. 88. 

 Palmate, with lobes or ribs radiating like the fingers of the open hand, 



pp. 34, 40. 

 Palmate-pinnate, the primary ribs arranged in palmate order, giving off 



secondaries in pinnate order, p. 35. 

 Palmate-reticulate, the primary ribs arranged in palmate order, the 



secondaries rapidly forming a mesh work, p. 65. 



Palmatifid, leaf-blade cut about half-way in, in palmate manner, p. 40. 

 Palmatisect, cut deeply into lobes in palmate manner, p. 40. 

 Parallel- veined, with the principal ribs running side by side for some 



distance, p. 33. 

 Parasite, a plant which derives some or all of its food from another 



living organism. 



Pari-pinnate, pinnate with equal pairs and no odd lobe, p. 44. 

 Peltate, shield-shaped with the stalk in the middle of the lower surface 



p. 37. 



Pentastichous, in five vertical orthostichies or ranks, p. 6. 

 Periderm, the corky layers of the cortex. 

 Petiolate, having a leaf-stalk, p. 17. 

 Petiole, the leaf-stalk, p. 17. 



Petiolule, the stalk of a leaflet in a compound leaf, p. 42. 

 Photo -synthesis, the building up of carbohydrates from carbon-dioxide 



and water under the influence of light, p. 95. 

 Phylloclade, a branch so flattened, &c. as to resemble a leaf. 

 Phyllode, a petiole flattened so as to resemble and behave like a leaf. 

 Phyllotaxy, leaf-arrangement on the shoot, p. 4. 

 Physiology, the study of the functions performed by living organs. 

 Pilose, softly hairy, with rather long hairs, p. 37. 

 Pinnate, with leaflets arranged along the opposite sides of the common 



petiole, p. 40. 

 Pinnate -arcuate, venation in which the secondary veins curve forwards 



towards the apex and there end, p. 58. 

 Pinnate-looped, venation with the secondaries arranged in pinnate fashion 



and looping forwards on to the next secondary, p. 58. 

 Pinnate -reticulate, venation pinnate, but the secondaries rapidly breaking 



up at their ends into a meshwork, p. 59. 



Pinnatifid, leaf-blade cut about half-way in, in pinnate fashion, p. 40. 

 Pinnatisect, cut deeply into lobes in pinnate manner, p. 40. 

 Plastidia, see Plastids, p. 74. 

 Plastids, minute corpuscles in the protoplasm, p. 74. 



