92 DEVELOPMENT OF ALLIUM URS1NUM. 



fibres which still adhere to it is quite dead (Fig. 1, a). Very rarely 

 two new bulbs adhere to the old axis. The young filiform roots, 

 which are but slightly branched, and are sprinkled with delicate 

 hairs, spring from the base of this year's axis, perforating the lower 

 part of the bulb. 



The bulb is surrounded by a single row of bristle-shaped short 

 threads (Fig. 1, c) without any dry skins. The outer portion is 

 at this time formed of the white membranaceous transparent 

 sheaths of the outer or lower leaf (Fig. 1, d), which is of some 

 height, and from whose contracted orifice the flower-stem (e) and 

 the petiole of the second leaf (f ) protrude. If the position of the 

 lamina of this outer leaf with respect to its sheath be accurately 

 examined, it appears that that surface (/3), which on account of the 

 brightness of its cuticle and its peculiar form is to all appearance 

 the upper surface, is turned from the aperture of the sheath while 

 in other plants it is turned towards it ; whereas the surface, which, 

 to judge from the dull aspect of the cuticle, the keel-like projection 

 of the midrib, as well as the margins which are somewhat rolled 

 back toward the tip, and the arching back of the tip itself, is 

 the under surface, forms apparently the continuation of the inner 

 surface of the sheath produced by the petiole.* This irregularity, 

 however, vanishes on closer inspection ; for then it appears that 

 the true upper surface has assumed all the peculiarities of the 

 lower surface, the dull aspect of the cuticle, &c., while the real 

 lower surface has the usual brilliancy, &c. of the upper surface ; 

 and this takes place with various modifications, sometimes merely 

 from a bending forward of the leaf so as to expose the under 

 surface to the influence of light, and sometimes from various 

 degrees of torsion of the petiole. 



The second leaf (f ), winch projects from the sheath of the first, 

 exhibits the same phenomena. It does not, however, by any 

 means surround the flower-stem with its sheath, but it stands in 

 the axil which the first leaf makes with it, and is turned with its 

 external surface (Figs. 2, 3) to the peduncle, and with the other 

 side ( 8 ) to the medial line of the first leaf. .It belongs therefore 

 to a lateral axis ; the back of its sheath, which is far shorter than 

 that of the first leaf, is thick and fleshy (Fig. 3) : the front is far 

 less so. The bore of the sheath is extremely narrow, since the 

 dorsal and frontal portion rest on each other, and it appears in a 



* Oil this side there are abundant stomata, whereas those on the other 

 side are few in number. There the walls of the cells are undulated, here 

 quite straight. 



