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Staber: The anatomv of Sesban macrocarpa 627 



The hadrome elements of the bundle varied according to the age 

 of the stem. In the younger sections the annular and spiral ducts 

 only were lignified. In the older portions, the libriform and med- 

 ullary ray cells formed by far the main percentage of the woody 

 cylinder. The ducts were typical, comprising the annular, spiral, 

 reticulated, and pitted. In the latter the edges of the pits were 

 slightly thickened. They had a very large lumen averaging 

 71.85 /i in width with a heavy wall of 3 /i in thickness, in con- 

 trast to the spiral and ring ducts which measured 28.2// across 

 their lumen, with a wall 3 /^ thick also. On the innermost edge 

 of the bundles were ducts which differed from the regular annular 

 ring ducts in having lateral lignified circular thickenings. In some 

 sections they appeared like distorted annular ducts, in others, the 

 ^ openings were decidedly lateral and showed no distortion. The 

 long pointed libriform cells averaged to have a wall of 1.5 /i and 

 lumen of 26.1 [i in the older parts. The walls were strongly lig- 

 nified and but slightly pitted by oblique slits. The parenchyma 

 cells surrounding the base of the bundles became lignified only in 

 the older stem. There was little wood-prosenchyma, but what 



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there was contained starch. 



Of particular interest in the study of any Galegeae are the 

 medullary rays in tangential section. Although these plants have 

 no common anatomical character, still three groups have been 

 found whose differences lay in the medullary ray construction.* 

 In cross section in this species, they were one* cell wide, had pitted 

 walls, and were filled with starch in the older stem. In radial sec- 

 tion they appeared rectangular in shape, forming long horizontal 

 rows, a characteristic of the Papilionaceae and of the Caesalpini- 

 aceae. Some rows comprised taller cells than others, which is 

 true, too, of Amorpha^ Indigofcra^ and Psoralen o^ the Podalyrieae.f 

 In the younger sections the cells were found to be taller than 

 those in the older parts. The story-like appearance of the cells in 

 the horizontal layers was pointed out by von Hohne and verified 

 by Saupe as occurring mostly in the Papilionaceae, also in the 

 Caesalpiniaceae. In tangential section, the cells form long 

 columns one cell wide, except that in some places, being two 



* Saupe, Flora 70 :303, 1887. 

 f Saupe, ioc. cit, 303, 



