466 Scientific Proceedings, Royal Dublin Society., , • 



spreading tangentially; laminae irregularly spaced, about- 3.0 cells thick; with 

 sehizogenous spaces filled with dark deposit. Bays conspicuous. 



T.S. — Eays fairly uniform in size, irregularly spaced, 30-35 in 2-rnm. field. 

 Total width in 2 mm. = 0'36 mm. Height = 012-0-40-Q-53 mm., 6-25 cells. 

 Width. =* 0-0'2-O-O5-0'07 mm., (1-2-), 3-, 4-, 5-ply. Margin sometimes 

 distinct; both margin and middle cells often with contents. — Fibres non- 

 septate. 



U.S. — Margin rarely distinct. — Chambered fibres, with vertical series of 

 crystals, frequent. 



25. African "Walnut." (Type II.) 

 No. 190, Piece of heartwood, from propeller of aeroplane. PI. XXXVIII, 

 figs. 97, 98; 99. 



Ochre brown, lustrous. Boey. Zones with close and with sparse 

 parenchymatous laminae alternating with one another. Vessels also zoned, 

 more numerous where the parenchymatous laminae are close. Frequent 

 tangential series of intercellular spaces, filled with black deposit; vessels 

 with black, deposit. Sp. gr. = 0*51. 



C.S. — Vessels compressed tangentially, scattered ; M.T.D. = 0-25 mm. ; 

 about 25 . groups in 2-mm. field, with contents. — Fibres thick-walled. 

 Circumvasal parenchyma spreads tangentially to form laminae, which often 

 develop intercellular spaces in tangential series, filled with dark secretion, 

 and extends radially along rays. Kays with dark contents. 



T.S. — Rays irregular, sides bowed, about 35 in 2-mm. field, total width of 

 rays in .2 mm. = - 29 mm. Height = - 46 mm. up to - 64mm. Width = 

 0040mm. 1-, 2-, 3-, 4-ply. Margin indistinct, no crystals. Middle cells 

 small, rounded, sometimes with contents. Crystals in vertical series in 

 transversely divided fibres. 



U.S. — Fibres non-septate. 



Note. — Neither this nor No. 219 resembles the wood of any species of 

 true walnut (Juglans) examined, and it may be inferred that the trade-name 

 of " African walnut " is given to them owing to their olive-brown colour. 

 No. 219 is easily distinguished from No. 190 by the ' sparse and' irregular 

 parenchymatous laminae. According to Bouget (14) wood furnished by 

 Coula cdulis Bn. (Olacaceae), and by some species of the genus Vitex (Verbe- 1 

 naceae), is exported from Gaboon under the name of walnut: 



26. African " Cedar." '■ ■ ,-, 



No. 43, from commercial source, labelled. '\ African cedar."- No record of 

 port of export. PI. XXX., fig. 54. ..,, ' , 



