I REMARKS ON THE STRUCTURE OF WOOD. XXxi 



Second Class. Pores nearly equal in size, but not uniformly distributed, 

 crowded in the spring wood and scanty in the autumn wood, annual rings 

 always distinct. Tamarix (medullary rays broad), Rhamnus catharticus, R. 

 Frangula, R. Alaternus (pores in wedge-shaped branching tails in most species 

 of Rhamnus), Prunus (medullary rays fine or moderately broad, broad in P. 

 MaJmleb), Terminalia chebula (a narrow belt of autumn wood without pores), 

 H.ij>pophae rhamnoides, Alnus incana. 



Third Class. Pores unequal in size, large and numerous in the spring 

 wood, smaller and scanty in the autumn wood ; annual rings always distinct. 



A. Medullary rays narrow or fine, generally all of one width. Cedrela Toona 

 (annual rings marked by a single line of larger pores), Rhus Cotinus, Fraxinus, 

 Tectona grandis, Morus alba, Celtis australis (medullary rays short, moderately 

 broad, but uniform), Ulmus montana, U. campesiris (the smaller pores of the 

 autumn wood in narrow wavy bands), U. effusa, Broussonetia papyri/era, Cas- 

 tanea vesca. 



B. Medullary rays of two classes, broad and narrow, the broad rays very 

 marked. Ailanthus glandulosa, Quercus pedunculata, Q. sessiliflora, Q. Cerris 

 (the smaller pores of the autumn wood generally arranged in irregular tails). 



Quercus Suber and Q. Ilex have a peculiar structure, fully described in 

 Mathieu's Fl. For. 256 and 263. The pores are arranged in wavy radial lines or 

 tails ; in Q. Ilex they are fine and not crowded in a belt of spring wood, in Q. 

 Suber they are large and more numerous at the inner edge of each annual ring, 

 without, however, forming a porous belt. Q. serrata has broad medullary rays 

 and middle-sized pores, and Q. semecarpifolia has fine and numerous medullary 

 rays. The wood of the other Indian Oaks has not yet been sufficiently examined. 



The wood of the Indian Leguminous trees merits special study. It is often 

 marked by wavy concentric bands of lighter-coloured tissue, which must not 

 be confused with annual rings. Albizzia odoratissima, Lebbek, procera and 

 stipulate, have large pores uniformly distributed, the pores often in groups of 

 2 or 3, and always enclosed in a patch of more open tissue, consisting of wood- 

 cells different from the mass of the wood. These patches are arranged in more 

 or less concentric lines, having the appearance of wavy bands. The medullary 

 rays are fine and numerous, and the annual rings are generally distinct. The 

 structure oiDalbergia Sissoo, Cassia Fistula, Xylia dolabriformis, Tamarindus 

 indica, and Acacia Catechu, is similar, but the wood of the two last-named trees 

 has no distinct annual rings. In Acacia arabica the pores are often close to- 

 gether in the inner part of each annual ring, and scanty in the outer belt. 

 Pterocarpus indicus (Padouk) has large scanty pores, more numerous and larger 

 in the spring wood, the pores of the autumn wood joined by white wavy concen- 

 tric lines ; medullary rays numerous, very fine. Sophora japonica, Robinia Pseu- 

 dacacia and Gleditschia triacanthos, have a porous belt of spring wood, the 

 autumn wood being firmer, with few pores. Another group is marked by having 

 the pores arranged in wavy, concentric, or oblique lines. Cytisus Laburnum, 

 C. alpinus, and Cercis Siliquastrum, a small tree with cordate leaves and pink 

 flowers of the Mediterranean region (cultivated at Kabul as Arghawan, J. L. 

 Stewart), have a belt of larger pores in the spring wood, while those of the 

 autumn wood are arranged in concentric and oblique wavy lines and patches. 

 Ulex europceus, the common Furze, has all pores in oblique belts, forming a net- 

 work of rhomboid meshes. Tamarindus indica has a similar structure, but no 

 distinctly marked annual rings. 



