10 CONTENTS AND 



CHAPTER XL THE STEM, OR ASCENDING AXIS. 69. 



161, Definition, #, cause of its ascent. 162, Direction horizontal erect pro- 

 cumbent ascending subterranean. 163, Annual perennial. 164, Distinction 

 in regard to size, &c. a, tree , shrub c, herb. 165, Most distinctive property 

 of stem. 166, Buds. 167, Leaf-bud. 168, The scaly envelopes. , Scales not 

 formed in hot climates, &c. their design. 169, Bud terminal, develops a simple 

 axis, a, axillary, developes branches, , adventitious. 170, Branch. 171, 

 Thorn, a, its nature, &c. 3, distinguished from prickles. 172, Node inter- 

 node, a, how formed why the axis diminishes upwards. 173, Arrangement of 

 branches, 174, spiral, a, modifications circular, how caused. 175, Alter- 

 nate opposite whorled. 176, Same of the branches. a, Two classes of stems. 

 177, Subterranean stemless plants varieties. 178, Bulb, <z, tunicated 

 scaly, 3, how renewed, e, bulblets. 179, Corm. ISO, Tuber. 181, Rhizoma. 

 182, Creeper, a, repent stems, their use. 183, Varieties of aerial stems. 184, 

 Caulis. 185, Runner. 186, Scape, a. culm. 187, Vine a, tendril. 188, Twin- 

 ing stems their direction. 189, Trunk a, its dimensions. Note, Illustrations, 

 b, its duration. Note, Illustrations. 190, Sucker. 191, Offset. 192, Stolon. 193, 

 Plurality of trunks #, Banyan Mangrove. 



1. PHYSIOLOGICAL STRUCTURE OF THE EXOGENOUS STEM. 77. 



194, Structure of herbaceous stems 195, of the first year's growth of perennial 

 stems, a, basis of the distinction of Exogens and Endogens. 196, Exogens. 197, 

 Endogens. 198. Parts of the exogenous structure. 199, Pith. 200, Medullary 

 sheath. 201, Wood number of layers. 202, Layer consists of, a, arrangement 

 of its parts. 203, Alburnum duramen. 204, Medullary rays. 205, Bark, its 

 parts. 206, its structure cork liber. 207, New- layer, how formed, , outer 

 layers, why shaggy horizontal fibres, 6, qualities resident in, c, its peculiar 

 vessels. 



2. FUNCTIONS OF THE STEM. 80. 



208, Conveyance of sap, 209, through what portion its course elabora- 

 tion descent. 



3. OF THE ENDOGENOUS STRUCTURE. 81. 



210, Its peculiarity. 211, Composition. 212, Each bundle consists of, a, mode 

 of increase. 



CHAPTER XII. THE LEAP. 82. 



213, Its importance character. 214, How distinguished. 215, Color autum- 

 nal hues, a, due to what chlorophyll changes, b, color of flowers. 



1. VERNATION. 82. 



216, Meaning of the term leaf-bud how compacted, a, illustration. 217, 

 Forms of vernation, 1, Equitant 2, Obvolute 3, Involute 4, Revolute 5, 

 Convolute 6, Plaited 7, Circinate. 



2. ARRANGEMENT. 83. 



218, In the bud after the axis is developed, 1, Scattered 2, Alternate 3, 

 Opposite 4, Verticillate 5, Fasciculate. 219, How these forms may be reconciled 

 with the spiral, a, illustration b, Alternate explained, c, Opposite or whorled 

 explained. 220, Leaves radical cauline ramial. 



3. ORGANOGRAPHY. 84. 



221, Nature of the leaf lamina sessile petiolate. 222, Petiole its form 

 1, Compressed 2 Winged 3, Amplexicaul. 223, General form of the lamina 

 base apex. 224, Leaf simple compound. 225, Physiology. 226,Venation 

 its organs. 227, Midrib nerves. 228, Veins veinlets. 229, Modes of Venation. 

 1, Reticulate 2, Parallel 3, Forked. 230, Varieties of reticulate venation, 1, 

 Feather-veined 2, Radiate-veined 3, Varieties of parallel venation. 



4. FORM OF FIGURE. 86. 

 231. Theory of form dependent on venation. 232, Forms resulting from tho 



