11 
composition, but to position in regard to water supply or conser- 
vation. Nevertheless, detailed investigations of typical portions 
of the Kew lawns revealed some facts indicating that there are 
differences between species of grasses and other lawn plants in 
their power of drought resistance, 
One of the commonest of the grasses in the Kew lawns is 
Lolium perenne, and green plants and even dull green patches cf 
this could be found in most areas where excessive tramping by 
visitors had not worn the turf away. Indeed, of the grasses 
normally present, the perennial rye-grass claims first place as a 
drought-resister. Yet, on many of the fully exposed lawns, it 
eventually became, last summer, as parched as its associated 
species. Species of Poa and Festuca were almost entirely absent 
in the green state from unwatered spots. Only one patch, not 
far from the Main Gate, of Festuca ovina, remained partially 
green, and individual plants were also found near the Temperate 
House. at ium should often survive green while species 
of Festuca should almost always become parched is difficult to 
explain. Anatomically the leaves and shoots of Festuca ovina, 
fF. duriuscula and other species, are xeromorphically constructed 
with their often subulate, rolled or folded leaves, in which the 
stomata are well protected in grooves on the inside of the leaf 
which possesses much sclerenchymatic tissue around the vascular 
bundles. Loliwm perenne has, on the contrary, leaves and shoots 
typical of a mesophytic grass, being glabrous with shallow 
grooves, not specially protected stomata and very little scleren- 
chyma, that which is present not forming girders to the vascular 
bundles. It is possible that an explanation is to be found in the 
root-system, for Lolium is a deep-rooted, generally tufted grass, 
and its subterranean system would appear to be more extensive 
than that of some, at least, of the common species of Festuca 
and Poa. That the root and rhizome system is of considerable 
importance is also shown by the survival of Agropyron repens. 
This plant is, of course, not a normal constituent of lawns, but 
some considerable patches occur in the grass near the Herbarium. 
The grass here was, in spring, chiefly composed of Arrhenatherum 
avenaceum, Alopecurus pratensis, Festuca duriuscula, Poa pratensis 
and Dactylis glomerata. Hay was cut early in June and by 
August very few remains of the named grasses were to be seen 
above ground. A tall green growth of Agropyron repens had 
taken their place over part of the ground which had certainly 
not been watered. The leaves of the couch-grass are not 
markedly xeromorphic in structure and the extensive under- 
ground stolons are its most noteworthy characteristic and would 
also account for its vegetative development during dry weather. 
Partly green specimens of Agrostis, which were found in the 
lawn near the Kew Palace and others near the Temperate House, 
would also appear to owe their preservation to nodal rootings 
and stolon production. A few of the coarser grasses survived 
in places. A green patch of Dactylis glomerata was observed 
