1217 
ON THE MIXED HERBAGE OF PERMANENT MEADOW. 
were one of the two unmanured ones, Plot 9 (mixed mineral manure and ammonia- 
salts), and Plot 14 (mixed mineral manure and nitrate of soda). 
In connexion with this subject it must be borne in mind that in many perennial 
plants, while the main body and principal branches of the root persist from year to 
year, the fibrils and root-hairs, as before mentioned, die off, and are renewed only when 
circumstances are favourable. The relatively early or late period at which root-growth 
of this character takes place would naturally affect the vigour of the plant and influence 
it for good or ill in its competition with others.* 
Root-stocTc, rhizome, &c .—Under this head we may include, for our present purpose, 
those portions of the root not directly concerned with the absorption of moisture or of 
food from without; those which are more or less woody or succulent, and which serve 
as holdfasts, as conduits, or as depositories for water and nutritive matters. More often 
than not these organs, in a strict botanical sense, are underground stems, having the 
internal structure and mode of growth of stems or of branches, and not of roots proper. 
It is not necessary to go into detail on these points here ; suffice it to say that, as a 
general rule, any portion of the plant, subterranean or not, which bears leaves or scales 
(which are the rudiments of leaves) or buds, is to be considered as a stem or branch, 
and not as a root. 
Speaking broadly, the object of these structures is to fix the plant in the soil, to 
enable it to avail itself of the food in the deeper layers of the soil, by emitting feeding 
roots when the conditions are favourable, and at greater depths than is, as a rule, 
possible in the case of fibrous roots, to store up water and nutritive matters, to force 
their way by progressive growth at their tips into fresh and unoccupied territory, or 
to make their way into that occupied by them neighbours if these be too weak, either 
intrinsically or from force of circumstances, to resist the intrusion. Often the subter¬ 
ranean stem or branches serve the purpose of propagation or of reproduction. Often, 
too, they serve, to some extent, as organs of locomotion; for instance, the stock con¬ 
tinues to grow at one end, year after year, the opposite end gradually dying away. In 
the course of a few years the plant, therefore, occupies quite a different position from 
that which it had at first. 
The details of these differences in form and structure are given in the ordinary text¬ 
books of botany, though little is therein said upon them from our present point of 
view. For our purposes we may speak of these “ stocks ” and “ root-stocks ” as : 
1. Elongated and more or less branched, either descending vertically or spreading, for 
* On the general question of root-growth and root absorption the most important paper known to us is 
that of Sachs in the “Land. Yersuch. Stat.,” 1859, iv., 1, wherein the researches of other experimenters 
are summarised. See also Micheli’s French translation of Sachs’ ‘Physiologie Yegetale,’ p. 187. The 
more recent papers of the same author, “ Ueber das Wachsthum der Haupt und Nebenwurzel ” (Arbeiten 
des Bot. Institut in Wurzburg, 1873, 1874) should also be consulted. [A paper of M. Mer “Des modifi¬ 
cations de structure et de forme qu’eprouvent les racines suivant les milieux ou ils vegetent,” read 
before the French Association for the Advancement of Science atRheims in 1880, is only known to ns by 
the brief abstract in the Bulletin of the Botanical Society of France, 1881, Rev. Bibl., p. 213.—Note added, 
October, 1882.] 
