264 



McDonald : TIic Doo's Mercury. 



forni of an arch, and the phiinulo hcluu'cs in tlu' manner 

 refered to fnrther on. 



After growing a few inches in lieight the ])hunnle straightened 

 itself, the hypocotyl becomes somewhat thicker, and kiter on 

 gives oil several adventitious roots from near the level of the 

 cotyledons, which grow obliquely downwards and assist in pulling 

 the young plant deeper in the soil. Towards August the plum- 

 ule gradually dies down to a point a little above its base, then 

 the remaining portion of the young plant, now buried in the 

 soil, comes to rest. Early the following year a bud, formed in 

 the axil of one of the colytedons, grows up to form the new stem, 

 emerging from the soil in the same arched manner as the 

 plumule did, and as, indeed, all the aerial shoots do w^hether 

 from seedling or mature plant. This shoot grows a httle larger 

 than the plumule did, and like it, sends down reserve food to 

 the neighbourhood of the hypocotyl. A bud is also formed in 

 the axil of the other cotyledon, but usually one remains un- 

 developed the first season or two, but ready to take the place 

 of the other shoot if any accident should befall it. 



On the approach of winter the second shoot decays, to be 

 replaced the next season by another one formed from a bud in 

 the axil of a scale-leaf near its base. 



The bud from the axil of the opposite cotyledon may now 

 also push its way up to the surface to form an additional shoot, 

 and the process described for the other repeated. Each 

 succeeding year the new shoots are gradually increased in 

 number, and become larger until maturity is reached. Some 

 of the shoots formed after the first two or three seasons do not 

 grow directly upwards, but obliquely, -through the soil, and after 

 they have died down to the surface they are replaced the suc- 

 ceeding season by others from buds at the nodes near the tips 

 of the stems left after decay of their aerial portions. In this 

 manner the plant comes to occupy a greater area, and judged 

 from above would seem to consist of many individuals, whereas 

 they are connected together by the underground portions, 

 sometimes for many years, and thus the unisexual colony is 

 established. If accident befalls any of the aerial shoots, there 

 are always subterranean buds ready to make up the loss. 

 Fig. 7 is a rough plan of the branching of part of a mature 

 plant, which will help to make the foregoing description clear. 

 As the shoots grow successively larger, so do the leaves borne 

 by them. 



Naturalist, 



