TRANSACTIONS OF SECTION K. 749 



strates once more tbe chemical ditference between the sapropeliferous rocks nnd 

 the humous rocks. 



As generally the peat is terrestrial and the sapropel is aquatic, and both 

 are autochthonous, so the bright coal on the one side and the dull coal on the 

 other have the same genesis. In other words, the peat and the bright coal on 

 the one hand, and the sapropel and ihe dull coal (cannel coal) on the other, are 

 derived from organisms which have lived and died m sifu {sur place)} 



If we are now to say a few words on the practical side, it must be regretted 

 that civilisation has for a long time been spoiling the peat bogs by drainage, and, 

 thus has killed them and made dead bogs which no longer produce peat. Britons 

 especially should remember that one day they will require a substitute for coal, 

 which ia diminishing rapidly. 



SATURDAY, AUOUST 4. 



The following Papers were read : — 



1. Contributions to the Root Anatomy of the Cupulifero! and of the 

 Meliacece. By W. J. Gallagher. 



There are two distinct types of rootlet in our native Oupuliferse : — 



(a) Rootlets free from a fungus. 



{b) Rootlets bearing an exotrophic mycorhiza. 



In (a) a root-cap, root-hairs, definite hypoderm, and cortex of upwards of 

 twenty concentric layers are present : in {b) root-cap, root-hairs and hypoderm are 

 absent ; there are not half a dozen concentric layers in the cortex ; the rootlets 

 are much shorter than in (a). The fungus-free rootlets are clearly not roots of 

 extension and fixation alone ; they are also absorptive, as shown by the well- 

 developed root-hairs. 



Cultures of the mycorhiza were made on various media, but all failed to give a 

 fructification. 



ilfe//ace«.— Twenty-two species were examined. In some species a layer of 

 cells with lignified but not specially thickened walls runs round the root-cap, 

 forming an internal sheath in its substance. It can be traced onwards as a con- 

 tinuation of the lignified hypoderm, moving quickly, step by step, outwards when it 

 reaches the root-cap, until it comes to lie in the last firm layer of the latter. In 

 roots possessing this structure the conducting bundle is differentiated closer up to 

 tbe root-apex than in the ordinary root. Probably the growth and elongation of 

 such roots are arrested, but their absorptive and translocative activities continue. 

 It is not impossible that this state may be attained in all species, though only ob- 

 served in some. 



Except in two species the hypoderm is suberised, and in the greater number 

 lignified as well. In addition to the outer tangential wall, sometimes the radial 

 wall, in whole or in part, and occasionally the inner tangential wall, are lignified. 

 The entire cell-wall may remain without local thickening — this is rare ; or the 

 outer tangential wall may present one of two types of thickening, and the radial 

 walls likewise two. Several species exhibit three of these types in the same cross- 

 section. In Cedrela Toona Roxb., Cedrela febrifmja Bl.,'and Simetenia Maha- 

 goni L., cells occur in which a thickenmg runs right round the radial, proximal, 

 and distal anticline walls, looking like a large Caspary's point ((^-cells of Rusaow). 

 In the Cedrela spp. the thickening is lignified, and a suberised lamella runs right 

 round the cell. 



Lenticels similar in outward appearance and anatomy to those of stem-members 

 are found on Dysoxylon alliaceum Bl., but not in D. excelsum Bl, a species of like 

 habit, size and anatomy. A cork layer is formed in these organs much later than 



' See Potoni6, Entitehung der Steinkohle (^Formation de la liouille'), Berlin, 1905. 



