544 Cook : A Synopsis of the 



ginal rib. In the short species the margin is flat belowand does 

 not become decurved in drying. In the other the thin edge is 

 closely folded under, and on drying the sides of the segments uni- 

 formly roll under, giving the dried leaves of the two species an 

 appearance even more dissimilar than in the fresh state. 



ii. The lower surface of the leaf of Thrincoma has a silvery 

 white layer of fine closely appressed hairs, all lying parallel to the 

 veins and forming a continuous covering. The fibers seem not to 

 be attached merely at one end, but along the side. They are firmly 

 adherent and are to be removed only by scraping or rubbing ; the 

 surface underneath is deep green like the upper side, but the fibers 

 remain in the grooves between the veins. In Thrinax pracceps the 

 lower surface of mature leaves is smooth and glaucous, a compara- 

 tively very slight hairy covering present in young leaves being 

 evanescent, though traces of it are usually to be found in the deeper 

 basal grooves. The glaucous appearance is due to the presence 

 of numerous white or hyaline points arranged in rows (stomata?). 

 The hairiness of one leaf and the glaucous character of the other 

 are probably to be looked upon as different adaptations for the 

 same purpose — the reduction of transpiration. 



12. The upper surface and the ligule of young leaves of Thrin- 

 coma are covered with a layer of wax in the form of small plates 

 or scales not present in Thrinax. 



Thringis gen. no v. 



Trunk columnar, rimose ; wood pithy. Leaves coriaceous 

 with equal veinules, silvery below with closely appressed whitish 

 pubescence. Fruits distinctly pedicellate, the pedicel with a bract 

 above the base. Seed cerebriform, irregular, with wide furrows 

 and convolutions ; surface smooth and shining. Embryo subapical. 



The characters of this genus are imperfectly known, none of 

 the specimens being complete. Supposing however, that the as- 

 sociation is a natural one, we have a genus with leaves and ped- 

 icellate fruits much more similar to those of Thrincoma than to 

 those of Thrinax, and at the same time a columnar, rimose and 

 pithy trunk like that of Thrinax and Coccothrinax. The seeds 







appear to differ from those of all related genera in the possession 

 of large irregular convolutions. The coriaceous leaves, small 



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