

INDEX SECOND. 



Medulla, peculiarity of, in Magnolias, 368. 



- varies in colour in different plants, 870. 



- character of its cells, 370. 



- - distinctions of the, stated by M. Aubert du Petit Thouar*, 37 1 . 



the membrane forming its cells is double, 372. 



- its- cells communicate by pores, 373. 



- its use to the plant, 374. 



- Mr. Knight's experiments on the, 375. 



new theory of its use, 377. 

 -- its functions soon cease, 378. 



-- is never obliterated in the sound stem, 380. 



- is never converted into wood, 381. 

 Medullary sheath, its character, 357. 

 --- vessels of the, 358. 

 -- cells of the, 359. 



- the arrangement of its vessels is regulated by circumstances, 

 361. 



Membranous texture, 70. 



Mesembryanthemum dolalriforme, structure of its leaf, 583. 



Michelius detected the seeds of Fungi, 451. 



Midrib of the leaf, 480. 



Mirbel, his opinion of vegetable life, 45. 



-- his remarks on fibrils, 207. 



- considers the cellular integument glandular, 323. 



- believes in the transmutation of liber, 329. 



- considers the cuticle a simple body, 599. 



- his opinion of the cuticular meshes, 604. 

 Monocotyledons, structure of their leaves, 559. 

 Mosses are very tenacious of life, 57. 



Musa sapientum, size of its leaf, 596. 



N. 

 Nerium oleander, structure of its foliar cuticle, 607. 



'. its foliar apertures, 612, 616. 



Nettle, structure of its sting, 643. 

 Nicholls, Francis, prepared skeleton leaves, 549. 



O. 



CEder began the Flora Danica, 18. 

 Olive oil, its components, 123. 

 Organic bodies, 4 1 . 

 Osculum scutiforme ovatum, 609. 

 -- annulare, 610. 



- annulare, 610. 

 -- quadrilaterale, 611. 



Oxygene gas, a healthy stimulus to roots, 220. 

 Oxygenous portion of the air is vitiated by roots, 219. 



P. 



Palms, structure of their stems, 294. 



- their mode of growth, 803. 



Papaver somniferum, structure of its root, 432. 



Parenchyma of leaves, its cellular structure, 590. 



Perennial herbaceous plants, structure of their roots, 437. 



Perforated vessels, their characters, 81. 



Petiole is a part of the leaf, 480. 



Petit 77iotfars, his observations on Dracena, 805. 



