254 



MORPHOLOGY. 

 171 



because, from want of material, I could say nothing of importance about 

 them, and I look upon mere guessing as a most objectionable method in 

 Botany. 



The great diameter of the porous tubes may, apparently, be regarded 

 as a general peculiarity in the ligneous structure of all climbing plants. 

 These have also strikingly large pores which (as I have never yet seen 

 in vessels) form even ramified canals, as is seen particularly well in 

 Bauhinia. 



2. Undeveloped Internodes. 



These have scarcely been investigated at all in the Dicotyledons. 

 Most of them remain very short, since they die below as they increase 

 upward. They belong principally to the subterraneous steins and 



171 Bauhinia: spec. Cross-section of a stem one-third of the natural size, a, Wood- 

 masses, partly with strikingly large porous tubes, b, Cortical substance, c, Bun- 

 dles of true wood, arranged in a simple circle, very evident on account of their whitish 

 colour, with straight radial medullary rays. The principal masses form eight larger 

 portions of wood, the cross-section of which resembles more or less a Japanese fan, with 

 an almost always distinguishable pedicle of cortical parenchyma, and at the same time 

 traversed in the interior by anastomosing streaks of cortical substance. With the 

 exception of the circle of vascular bundles (c), the rest of the wood is chiefly composed 

 of parenchyma ; and the medullary rays run in curving lines. The cortical tissue con- 

 tains liber-cells and liber-bundles, even to the very interior of the stem. The wood- 

 bundles (c) do not run vertically, but obliquely laterally ; yet the section in my 

 possession is only about a line thick. 



