54 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. i.xt 



be kept in view in an attempt to locate this wood in its 

 systematic position are — the pores, rays, indistinct rings, and 

 especially " spurious rings " of soft tissue. Somewhat 

 similar rings occur in a few British woods, but there the 

 tissue forming the rings is of different histological structure, 

 or is differently arranged. The indistinctly marked "annual 

 ring " is an attribute of tropical rather than of temperate 

 wood. Spurious rings, as seen in the fossil, are of common 

 occurrence in tropical trees, and have been used as diagnostic 

 characters in the classification of such timber, and in the 

 identification of even families and genera. 



They occur in the wood of species of Anonacete, Sapotaceie, 

 and Ebenacea;. They are very common in tropical Legu- 

 minos;e ; occur also in Guttiferte, Celastracea", Meliacea?, 

 Boragineie, and Urticace;c. 



Kecent woods, showing structural peculiarities most 

 closely identical with those of the stem described, are 

 found in the orders — Leguminoste, Urticacete, Sterculiace;c, 

 CombretacecT, and Boragineie, the senus C'ordia of the last- 

 named order presenting woods of very similar character, 

 whili?the tropical woods of the four first-mentioned are 

 distinguished by slight differences in the medullary rays 

 and the distribution of the pores. 



REFERENCES. 

 Gamble's Manual of Indian Timbers. 

 Marshall Ward : Timber. 

 Witham : Observations on Fossil A'ogetables. 

 Houlbert: Annales des Sciences Naturelles, 7th Series xxii. 

 Laslett : Timber and Timber Trees. 



PLATE. 



iieiiniduction of a photomicro^aviph of the surface of fossil, taken 

 with 1 inch objective by Method H., described on page 49. 



A Method of In-jection-stalnino Plant Vascular 

 Systems. By II. A. Kobertson, M.A., B.Sc. 



(Read 8th April 1897.) 

 There is the well-known method of A"on Hiihncl 

 (I'ringsheim's Jahrljiicher, xii., 1870, ]>. 47) of taking 

 advantage of the negative pressure of a strongly transpir- 

 ing branch or shoot. The vessels of such a branch, if cut 



