THE BOTANY OF BUILDING ESTATES 
85 
organism of plants and animals, phosphorescence is no rare 
phenomenon. Its appearance in plants prepares us for its occur- 
rence in the humbler animals, and its presence there ought to 
do away with any surprise at its occasional manifestation in the 
higher forms of animation. 
P. Walton Harrison. 
THE BOTANY OF BUILDING ESTATES. 
By Charles Nicholson, B.E.N.A. 
HEN a piece of land is cleared and cut up for building 
purposes, the removal of turf, digging of foundations, 
excavations for sewers, and other processes, necessarily 
cause a great disturbance of the surface soil, and what 
is not immediately built on forms a fine nursery for the straying 
seeds of innumerable plants, which readily germinate and grow 
in bare soil without much regard to its composition and texture. 
Such places are, therefore, often of much interest to the botanist, 
and are always worth a visit while the building is going on ; and 
even when the houses are built it often pays to inspect the 
gardens in their raw state, unusual plants being not infrequently 
met with in such places. The results of my own explorations 
in the neighbourhood of Hale End and Woodford Green, where 
much spasmodic building goes on, are set forth below, and 1 
divide the localities according to the nature of the ground, draw- 
ing special attention to the “casual” and “alien” plants met 
with in my wanderings. 
It will be desirable first to note the distinction between the 
terms native, colonist, and alien, when applied to plants and as 
defined by H. C. Watson in “ Cybele Britannica.” A native 
plant is apparently an aboriginal British species, which has not 
been introduced by human agency, and I shall treat as such, 
for the purposes of this article, all species included in the ninth 
edition of the “ London Catalogue of British Plants,” except 
those classed therein as aliens and colonists ; aliens being under- 
stood as presumably, or actually known to have been, introduced 
originally from other countries by man, but now more or less 
established in this ; colonists, as weeds of cultivated land or the 
vicinity of houses. By casuals, I mean plants commonly found, 
but not necessarily native, in other parts of the country, and 
certainly not native in this district. In this neighbourhood a 
building estate is apparently a piece of land on which one or 
more roadways are marked out, kerbed, ballasted with coarse 
shingle and then left to Nature’s tender mercies, a house or two 
being sometimes put up here and there just to show what is 
intended. The coarse shingle gradually gets covered with a 
