138 



MINUTE STEUCTURE OP THE STEM. 



cases can generally be referred to eccentric growth of some one 

 or more parts, as in flattened stems, or explained by the intro- 

 duction and more vigorous growth of supernumerary bundles. 



394. Extraordinary anomalies are afforded by the lianes of 

 tropical countries, woody climbers with distorted stems. They 

 belong chiefly to a few orders; namely, Bignoniacese, Mal- 

 pighiaceffi, Menispermacea;, and Aristolochiaeeje. A few inter- 

 L'stiug cases are shown in the accompanying figures, and are 

 sufflcieutly explained in the descriptive letter-press. 



■395. Spring wood and antnmn wood. The secondary wood an- 

 nuall3- produced in a temperate climate like ours exhibits certain 

 differences between the inner and the outer portion of the year's 



Fig. 113. Transverse section of the stem of a liana belonging to the order Malpighi- 

 a(:ea3 : m, pith ; h, the central portion of the wood, arranged in concentric layers around 

 the pith. (Duchartre.) 



Fig. 114. Transverse section of the stem of a liane belonging to the order Malpighi- 

 acese; m, the pith. The bark follows all the irregularities of the wood. (Duchartre.) 



Fig. 115. Transverse section of a liane belonging to the order Sapindaceiie : 6, pri- 

 mary woody body having its own pith m, and bark e'c; &', b', &', three secondary woody 

 borlies without pith, but having as thick a bark as the primary body. (Duchartre.) 



Fig. 116. Transverse sectio'i of the stem of aliane belonging to the onler Sapindaceas : 

 6, the primary or central woody body having its own pith m ; (/, b', b\ 6', a circle of un- 

 equal secondary woody bodies; b" , tertiary woody bodies. (Duchartre.) 



