434 JOURNAL OF FORESTRY 



In the Csesalpinioideje, vertical secretory canals have been described 

 by Guignard (i, 7), Mezger (8), Tschirch (4, pp. 770, 1054, et scq.), 

 Solereder (2, pp. 905, 1102), and others as characteristic of the second- 

 ary wood of Copaifera, Bperiia, Kingiodcndron, Prioria, Daniellia, and 

 Oxystigma. The writer has observed them in various species of the 

 first four genera mentioned, and also in Sindora snpa, and in an uni- 

 dentified Brazilian wood labeled "bate caixa," and rather closely re- 

 sembling Prosopis. In the various species examined the canals are in 

 concentric lines, more or less continuous, appear as delimiting the 

 growth rings, and exude an oily substance which stains the surface of 

 the wood. They serve as a dependable diagnostic feature, and their 

 presence can be determined with a hand lens and often without it on 

 account of the exudations. 



According to Guignard (loc. cit.) the canals in Daniellia thiirifera 

 and D. oblonga are very much like those in Copaifera, except that in 

 the latter they are arranged in regular circles in the early wood of suc- 

 cessive growth rings, whereas in Daniellia they are more irregularly 

 disposed and the tangential anastomosing is not so marked. He also 

 reports that radial anastomosing occasionally occurs. In both genera 

 the epithelial cells have larger nuclei than the surrounding cells. The 

 walls next the cavity of the duct are noticeably thinner than in other 

 portions of the cells, but these walls, even in their thickest portions, are 

 never lignified. The epithelial cells are usually short, but in contact 

 with wood fibers they elongate somewhat. Trees belonging to this 

 group are the source of valuable balsam, which is obtained by tapping. 



Rutacecu 



Although, as previously stated, secretory cavities have been recorded 

 in Bvodia and Xanthoxylum, Solereder (2, p. 856) states that these are 

 without doubt in the nature of mucilage spaces, and (p. 181) that char- 

 acteristic secretory cavities are completely absent in the wood. No 

 reference to intercellular canals in the wood has been found. 



Two woods from the Canal Zone, namely, Xanthoxylum elephan- 

 tiasis and X. pittieri, show numerous small vertical canals in irregularly 

 disposed concentric arcs and semicircles. Here and there in the rows 

 one may find large masses of parenchyma like pith-flecks, with or with- 

 out intercellular canals. Another specimen from Panama — a soft yel- 

 lowish wood with reddish-brown streaks and highly tanniferous — con- 

 tains a few canals. This wood is evidently a species of Xanthoxylum. 

 The canals are without epithelium and the irregular disposition of the 

 limiting cells affords evidence of the lysigenous development. The con- 

 tents test for mucilage. The writer has noted similar canals in Citrus. 



