1893.] the Flora of the Pollard Willows near Cambridge. 87 



(3) Three sparrows' nests from section H. 

 Anthriscus sylvestris, stem. 



Garduus sp., large numbers of ripe fruits. 



Phragmites communis, Poa annua, pratensis and trivialis, 

 Lolium perenne, Bromus mollis, Deschainpsia caespi- 

 tosa, Festuca ovina, Dactylis glonnerata, stems and 

 panicles. 



(4) Two sparrows' nests from section D. 



Much like the last, especially in containing no Galium, but 

 including also Agropyrum repels, and Alisma Plantago. 



(5) Three blackbirds' nests from section H. 



Galium Aparine, stems, &c. 

 Phragmites communis, stems, &c. 

 Ui'tica dioica, stems. 

 Anthriscus sylvestris, stems. 



(6) One nest (? sparrow) from section H. 



Stems, leaves and inflorescences of Gynosurus cristatus, Tri- 

 ticum, vulgare, Alopecurus pratensis, Avena sp. ?, Phrag- 

 mites communis, Glyceria aquatica, Agropyrum, repens, 

 Lolium perenne, Poa annua and pratensis, Deschampsia 

 caespitosa, and most interesting, perhaps, of all, pieces of 

 Elodea canadensis, which were living when added to the 

 nest. 



(7) One wren's nest from section H. 

 Daucus Carota, stem and fruit. 

 Galium Aparine and several grasses. 



It is thus evident that many grasses are probably distributed 

 by birds, and also other plants, such as Galium, Lamium, An- 

 thriscus, &c. 



Turning now to the question of the nutrition of these plants, 

 the first point to be noticed is the great size and vigour of many 

 plants. Specimens of Sambucus 2 — 3 metres high and 2 — 8 cms. 

 thick are common; the largest found was 4 metres high and 16 cms. 

 thick. In this case the roots were observed to have sjrown right 

 down through the trunk of the willow into the soil, and probably 

 this occurs in other cases. A plant of Acer was 5 cms. thick. 

 Rosa, Rihes, Crataegus, &c. were often well grown, and bearing 

 many flowers. Herbs such as Galium and Grasses also grow well, 

 many trees being simply beds of them. 



Of the 80 species, 64 are perennial (23 shrubs or trees), 5 bien- 

 nial, 11 annual. Probably, however, this fact is not of importance, 

 as the annuals become established in the trees; among them is 

 included Galium Aparine, the commonest species of all. 



