EFFECTS OF ENVIRONMENT ON PLANTS. 125 
(46.) Skylark (Alauda arvensis). — A common visitor in cold 
weather, and occasionally one or two may be seen at 
other seasons. Flocks consisting of two or three 
hundred came into town in January last. 
(47.) Swift ( Cypselus apus). — A regular summer visitor, but 
do not know of any breeding in London. 
(48.) Kingfisher ( Alcedo ispida). — A rare visitor. Seen oc- 
casionally by the Serpentine, and generally during the 
winter months. 
(49.) Cuckoo (Cuculus canorus). — Occasionally seen in spring 
and summer, but perhaps more frequently in autumn. 
On October nth last, a foggy morning, I saw a 
Cuckoo (no doubt a young bird) being chased by three 
rooks in Kensington Gardens. This is the latest date 
on which I have seen this species in England. 
A. Holte Macpherson. 
(To be continued.) 
THE EFFECTS OF ENVIRONMENT ON PLANTS. 
I. Altitude. 
jlAVING discussed 
dwarfing 
as a peculiarity of alpine 
plants,* it will be useful to consider the variations in 
the colour of the flowers which are frequently asso- 
ciated with it. 
Blue Alpine Flowers. — Certain very blue flowers are con- 
spicuous on high mountains, such as the gentians, polemoniums, 
mertensias, and so forth. In Custer County, Colorado, on the 
slopes of the Sangre de Cristo range, I found Omphalodes nana, 
var. aretioides, Mertensia sibirica and M. lanceolata, and Echinosper mum 
floribundum among the Borraginaceas ; Campanula rotundifolia, C. 
uniflora, and C. planiflora among the Campanulaceae ; Swertia 
perennis, Gcntiana serrata, G. barbcllata, G. heterosepala, G. humilis, 
G. bigelovii and others among the Gentianaceas ; Polemonium 
confertum and other species of that beautiful genus of Polemoni- 
aceae ; Pentstcmon cccspitosus, P. acuminatus and some other Scro- 
phulariaceae ; as well as various species of less importance, all 
having blue flowers, and forming quite a prominent feature in the 
landscape in many places. 
Blues and pinks tend to replace reds and yellows in alpine regions. 
— In Wet Mountain Valley, Colorado, there occurs a peculiar 
genus of Scrophulariaceous plants called Castilleia. From the 
way in which the bracts are often tipped with brilliant colours, 
the local name of “ paint-brush” has been given to them. In 
See Nature Notes, vol. ii., p. 15. 
