366 
Report of the Consulting Botanist on 
great number of these worms, which have been developed in 
the gall, and form a white cotton-like mass in its centre. 
Sufficient care is not taken to destroy these worms. When 
the gall is sown with the seed, the moisture of the soil revives 
them ; they escape from the gall, and find their way to the 
flowers of the growing crop. I have treated of this disease at 
some length in this number of the ' Journal.' * 
Several cases of weeds proving injurious to stock have been 
submitted to me, on which I have reported. A remarkable case 
of injury to vegetation from a minute alga (^Pleurococcus vulgaris) 
was brought under my notice. This microscopic plant de- 
veloped in the mould of the hotbed from which I obtained it 
with such marvellous rapidity that it completely covered all the 
particles of the mould, and so prevented the terminations of the 
rootlets obtaining nourishment from the soil. 
Serious injury was done to a young crop of mangolds by the 
burrowing of the larva of Anthomya Betce in the leaves. 
A field of wheat suffered from the larva of Chlorops lineata, 
which attacked the tender ear, and destroyed it. 
XIX. — Report of the Consulting Botanist on Laying down 
Land to Permanent Pasture. 
[Presented to the Council at their Meetuig on February 1, 1882.] 
In determining the grasses best fitted for laying down land in 
pasture, it is important to take into consideration the term of 
life of the different species. 
Many grasses are so short-lived that they do not survive the 
exhaustive process of seeding. One-third of our indigenous 
grasses die in this way, usually at the close of a single season, 
and are therefore called annual grasses. Not only the portion 
of the plant above ground, but the roots also perish, and the 
species is preserved from year to year only by the seed. The 
remaining two-thirds are grasses in which the process of flower- 
ing does not so completely exhaust the plant as to kill it. The 
life of the individuals in these grasses is continued from year to 
jear, and seeds are annually produced. Though the plant may 
be killed down by the winter's cold, the roots, with their crown, 
remain alive, and increasing in their hold on the soil, are able 
to secure a more speedy and extensive growth than can be 
produced under the most favourable circumstances from seeds. 
While annual grasses, or those having a short term of life, like 
* Vide pp. 346, et seq. 
