GLOSSARY 325 



Lenticel, cork-like spots on twigs and branches which admit air, &c. 



Linear, very narrow, with parallel edges, as in Fig. 6, p. 22. 



Lobe, one of the parts into which a leaf is cut, when the incisions are too 



deep and distant for teeth but too shallow for segments ; as in 



Fig. 9, p. 27. 

 Looped, venation where the secondaries turn at their ends and join on to 



the next secondaries in loop-like curves, p. 34. 

 Maculate, spotted or blotched, p. 37. 

 Margin, the edge of the leaf, p. 27. 

 Membranous, thin and more or less translucent, p. 37. 

 Mesophyll, softer green tissue between the ribs and veins of the leaf, p. 86. 

 Middle lamella, the primary cell-membrane recognisable in the median 



plane of thickened cell-walls, p. 70. 

 Midrib, the principal rib running approximately up the central axis of 



the leaf, p. 48. 



Morphology, the study of form and development. 

 Mucronate, with a short, sudden apical point, as in Fig. 10, p. 28. 

 Multi-foliolate, with many leaflets, p. 44. 

 Node, the joint-like swelling where leaves are inserted, p. 4. 

 Nodose, where the nodes are close and prominent and knot-like. 

 Nucleus, an important protoplasmic body in the cell, with essential 



functions in cell-division, reproduction, &c., p. 74. 

 Nucleolus, a small mass of protoplasm recognisable in the nucleus, p. 74. 

 Nutation, a nodding movement described by the apex of rapidly growing 



shoots, p. 114. 



Nyctitropic, the night-position observed in many leaves, &c., p. 112. 

 Obcordate, cordate, but reversed, the narrow end next the leaf-insertion, 



as in Fig. 8, p. 23. 

 Oblong, like an ellipse flattened so that the sides are parallel for some 



distance, as in Fig. 6, p. 22. 

 Obovate, ovate, but reversed, the narrower end next the leaf-insertion, 



as in Fig. 8, p. 23. 

 Obscure, venation when the venation is very slight, little or no more 



than a midrib being discernible, p. 55. 

 Obtuse, bluntly rounded at the apex, as in Fig. 10, p. 28. 

 Ochrea, sheath formed by conjoined stipules round the shoot, p. 20. 

 Octostichous, in eight orthostichies or vertical ranks, p. 6. 

 Oosphere, the egg-cell ; the primordial cell which after fertilization will 



become an embryo, p. 77. 



Opposite, leaves in pairs at each node and inserted on opposite sides, p. 7. 

 Organography, the description of the organs of the plant. 

 Orthostichy, a vertical rank of leaves, &c., p. 7. 

 Osmotic, having a powerful attraction for water and capacity for holding 



it under certain conditions. 



