Keegan : The Sycamore. 103 



course of the nerves ; the stomata are of medium size, and have 

 no accessory cells, but are very numerous, their number per 

 square mm. being about 400 ; the leaf is about 165 /a thick ; 

 at the base of the petiole the separated vascular bundles form 

 a closed ring, from which nearer the blade other bundles are 

 emitted, making 7 in all. On 8th August the blades held 67 

 per cent of water, and the dried substance contained 3.5 per 

 cent, wax, with very much carotin, but very little resin or fat 

 oil, 19.8 albumenoids, 3.4 quercitrin and tannin, some free 

 phloroglucin, and glucose, a moderate quantity of pectosic 

 mucilage stained with phlobaphene, no reserve starch (very 

 much in the fresh leaf), much oxalate of calcium, and 11. 2 ash 

 which had 26.2 per cent, soluble salts, 14.9 silica, 26.4 lime, 

 5.8 magnesia, 5.3 P'-^O . and 4.4 SO^, there were some man- 

 ganese and soluble carbonates. The ash of the brown autumn 

 leaves (with petioles) amounted to 12. i per cent, with 20.7 per 

 cent, silica, 41.9 lime, and i.i P-0^. The leaves contain 

 inosite, according to Pick. The special feature, however, is the 

 lavish plaster of wax on the lower epidermis, which rapidly 

 separates from boiling alcohol in gelatinous masses ; its formula 

 would be near C^^'H^'^O*. The early cessation of the foUar 

 vegetation in this species of Maple forbids any exhibition of the 

 magnificent crimson autumnal colouration so admirably 

 beautiful in soyie of its congeners. 



Flower and Fruit. — The inflorescence assumes the form 

 of a pendulous cluster (raceme) which exhibits every gradation 

 from hermaphrodite flowers with large ovaries to those in which 

 the ovaries are reduced or entirely absent. The pistil consists 

 of two carpels joined to form a flattened two-chambered ovary, 

 with two ovules in each chamber, "fhe floral parts contain 

 no carotin, but have much quercitrin and glucose (the disc 

 glistens with drops of nectar) , while the ash of the whole thryse 

 yields 48.5 per cent, soluble salts, 14. i lime, 3.8 magnesia, 

 12.4 P'^O^, 6 SO^, with traces of chlorine, magnanese, etc. In 

 the fruit, which is a double samara (winged achenes), one 

 ovule in each chamber enlarges to a rounded seed, which is 

 wholly occupied by the embryo, and fills up the globular 

 chamber ; the ripe seed is made up of an external tegument 

 (testa) composed of a cuticle, two layers of thin cells, a com- 

 pressed membrane, and a layer of cells with crystals of oxalate 

 of calcium, also of an internal tegument (tegmen) of five rows 

 of cells ; a refractive plate, which is the relic of the absorbed 



, 1909 March i . 



