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THE ESSEX NATURALIST.
It will be seen immediately that the order into which Unwin
has grouped the species according to their degree of modification
coincides with that in which they fall as regards humidity
requirements, thus showing a direct relation between the two.
This, then, provides the reason why the humidity factor exerts
such a dominant influence over the lives of woodlice ; the
process of adaptation to their air-breathing environment still,
apparently, creates one of the major—if not the greatest—
problem in their existence. Moreover, the same need for a
correct moisture environment accounts for their tendency to
hide beneath stones, among roots, under bark, etc., where there
is less loss of moisture by evaporation. Gunn (1937), it may be
added, has demonstrated experimentally a very definite hygro-
kinetic action in the species P. scaber.
(To be continued.)
STRAY NOTES ON SOME ESSEX PLANTS.
By W. D. GRADDON, B.Sc.
PAPAVER LECOQII. Lam.
August, 1939 : A single very fine plant was seen in a cabbage field
near Fyfield. The sap was bright yellow, the pod very long and the
leaves much dissected into acute segments. The specimen was added
to the Club's herbarium in the Stratford Museum.
CARDAMINE FLEXUOSA. With.
April-June, 1937 : Plentiful in the lower parts of Knighton Wood.
VIOLA ODORATA. Linn.
In April, 1939, the hedge-banks around Strethall abounded in large
clumps bearing many pure white flowers, with a short purple spur.
CLAYTONIA PERFOLIATA. Don.
In May, 1938, this appeared abundantly in my garden adjoining
Knighton Wood, Woodford, and has there thoroughly established itself.
MALVA MOSCHATA. Linn.
July, 1939. Several fine plants with pure white flowers were seen on
roadside waste near Great Sampford.
MYRIOPHYLLUM SPICATUM. Linn.
August, 1939 : Abundant in Hatfield Forest lake.
VALERIANELLA DENTATA. Poll.
June, 1938 : Plentiful on roadside waste near North Weald church.
INULA HELENIUM. Linn.
August, 1939 : A very large colony of this robust, conspicuous plant
was growing in damp ground near Widdington. A specimen was taken
for the Stratford Museum herbarium.
HOTTONIA PALUSTRIS. Linn.
In two Epping Forest ponds, in one of which I have seen it each June
from 1930 to 1938.