Colonisation of a Dried River-Bed. 189 
Of the plants encroaching from the land, eighteen had taken 
some considerable hold, of which five were locally dominant. 
PLANTS ENCROACHING FROM LAND. 
Few. Considerable Numbers. 
Scattered. 
Asparagus officinalis. Antlioxantlmm 
(1 plant). 
Convolvulus 
sepinm (1.) 
Dipsacus sylvestris. 
Epilobium 
parviflorum . 
Field Pea (1.) 
Dominant locally. 
Chenopodium Bonus- 
Henri cus. 
C. alba. 
Equisetum palustre. 
Polygonum 
la pa til ifolium. 
Urtica dioica. 
odora turn. 
Agrostis vulgaris . 
Bromus stcrilis. 
Glycerin distans. 
Hoi cus l ana tus. 
Hamulus Lupulus. 
Polygonum Hydropiper. 
Papaver Rhceas (2.) P. persicaria. 
Phalaris Rumex conglomeratus. 
canariensis (2.) R. obtusifolius. 
Primus communis. Solanum dulcamara. 
Sonchus arvensis. S. nigrum. 
Trifoliumrepeus(2.) Tussilago Farfara. 
Vicia Cracca (1.) 
Many of them grew with unwonted luxuriance, notably the wild 
oat, which reached a height of seven feet, the flowering head being 
eighteen inches long. Also Solanum nigium, which Hooker describes 
as “ having an erect stem six to twenty-four inches, rarely more ” 
grew as large and straggling plants with stems four feet six inches 
long, and with very much the vegetative habit of S. dulcamara. These 
luxuriant growths seemed well accounted for by the original rich¬ 
ness of the soil, the sufficiency of moisture, and the unusual warmth 
of the sun, but these very factors appear to have hindered many 
plants from growing there that one would have expected, e.g. 
Papaver Rhceas , many Composites and Leguminosae growing in the 
adjacent fields were almost unrepresented. Yet such Composites 
as Leontodon and Sonchus would appear to have had every chance 
of having their seeds scattered by the wind, and sticking to the 
damp mud. 
There were also extremely few Leguminosae: I dug up all I 
could get, and found that Trifolium repens and Vicia Cracca had no 
tubercles developed, but that the field pea had exceptionally large 
ones, so the evidence was conflicting as to tubercle development in 
such a soil. 
Another plant that appeared to have every opportunity of 
entering the new domain, and yet did not avail itself of it, was 
Convolvulus sepinm . This grew in great quantity on one of th^ 
