Feb. 18f'3.] BOTANICAL SOCIETY OF EDINBUKGII. 575 



median groove on the npper surface corresponding to a 

 somewhat more distinct ridge below. 



Hypocotyl. — The hypocotyl, on which the cotyledons 

 are raised above the ground, is short, slender, and terete, 

 of a pale green colour on the shaded side, but frec[uently 

 tinted with red on the face turned towards the sun. 

 Under normal conditions it reaches a length, according to 

 Sir J. Lubbock, of 5 mm. or 1 era. ; but, if grown in a 

 shaded situation or among grass, it may become much 

 longer, frequently attaining a height of from 2 to 2^ or 

 3 cm. 



Root. — The end of the radicle in most cases grows 

 vertically downwards, branching slightly, and forming a 

 strong tap root. The lateral rootlets are given off in four 

 rows, arranged in two double rows, one vertically below 

 each cotyledon, and corresponding to one extremity of 

 the diarch xylem strand, which lies in the plane of the 

 cotyledons. The members of each double row diverge 

 from one another at an angle of about 20°, while the 

 angular distance between the two double rows is about 

 160°. The root of Ukx thus agrees, in this respect, with 

 that of the other Geniste.p, and falls into Van Tieghem's 

 binary division of roots. 



Tubercules are formed on both main and lateral roots 

 very early indeed in the life of the plant, but they seldom 

 attain any large size. 



Plumule. — The first few internodes of the plumular 

 bud are, in the majority of cases, but slightly developed, 

 with the consequence that the leaves springing from the 

 corresponding nodes are crowded together immediately 

 above the cotyledons. The first plumular leaf lies in 

 a plane at right angles to that occupied by the cotyledons, 

 and the second leaf is placed almost opposite the first, but 

 slightly higher up. The angular divergence of h, indicated 

 by the opposite position of the first pair of plumular 

 leaves, passes over at the third or fourth leaf into one of 

 i, which, after a very few turns, is converted into a diver- 

 gence of f, and this finally becomes i] in the adult plant. 



Many variations, however, occur ; not unfrequently the 

 "I spiral is omitted, and the § follows directly on the ^ 

 arranoement. 



