1214 
MESSRS. J. B. LAWES, J. H. GILBERT, AJSTD M. T. MASTERS, 
Almost all the plants on the plots are perennials—very few are annual. The dura¬ 
tion of the plant in some cases is indeed increased by the rarity with which seeds are 
perfected. The hay-crop being cut when but few plants have had time to ripen seed, 
and some have not even been able to flower, it is clear that the annual plants have 
little chance of maintaining their ground. In other cases, however, seeds are produced 
abundantly. 
Hardiness, &c .—The hardiness or power of resisting frost or drought, especially 
during the growing season, is a matter evidently of foremost consequence. Although 
most of the plants can bear a very low temperature with comparative impunity, if in 
a quiescent state, yet the young growing shoots or leaves are liable to suffer injury 
from frost. Some of the plants on the plots are protected from the action of frost by 
the remains of the dead leaves of the former year; but while this protection may be 
useful in winter, it may be disadvantageous in spring by promoting premature growth. 
The early or late development in spring then becomes an element of considerable 
importance among the causes tending to the supremacy of certain plants over others. 
Supposing two plants to have started into growth together, it is obvious that the more 
hardy of the two would have a better chance of enduring the onslaught of frost 
at this critical period than the more tender one, and would hence gain the advantage 
over it. 
Apart from the varying effect of frost or other injurious circumstance on different 
plants, it has to be taken into consideration that different plants have different seasons 
of growth. All other conditions being equal, some species, or individuals by here¬ 
ditary tendency, start into growth earlier or later than others. It is clear that 
the late-growing species would be at a disadvantage when growing in association with 
more early developed plants of equal hardihood ; because the latter would have 
occupied the ground, to some extent, before the former had had time to develop 
themselves. 
So far as ability to withstand drought is concerned, it is certain that it depends 
most materially on the underground development, either of the stock or of the 
roots proper. A striking illustration of this has been given at p. 334, et seq,, of 
Part I. In considering the competition that is going on between one description of 
plant and another, the form, size, and direction of the leaves, the manner in which 
they are protected from the effects of excessive radiation, and their tendency to 
transpire much or little, according to the surface they expose to the air, &c., have also 
to be taken into account, as well as the variation in their anatomical organisation 
according to the circumstances under which they grow. These points are referred to 
in more or less detail under the head of the individual species ; but some general 
remarks may appropriately be given in this place. 
Roots and root-hairs .—It is necessary to draw particular attention to the generally 
recognised difference between the true feeding roots and those organs also commonly 
called roots, but whose office is that of transmitting or storing nutrient matter or 
