374 МВ. В. S. ADAMSON : AN. ECOLOGICAL STUDY 
А general comparison may be made of the flora of the caleareous elay with 
that given by Moss * for the corresponding woodlands of Somerset ; in the 
trees the chief difference is the great abundance of Populus tremula var. villosa 
and the presence of. (тих, neither of which is mentioned ах occurring in the 
* Oak-Hazel ? woods of Somerset. However, Ulmus glabra, Mill., the species of 
elm occurring in greatest quantity in this wood, as a native tree is practically 
confined to the East of England. With regard to the shrubs and ground 
flora the similarity is remarkable; of the shrubs, no species occurs abundantly 
in this wood which is not characteristic of similar woods in Somerset, and the 
similarities of the ground flora are almost equally striking, allowing for such 
differences as would be expected in two counties with such markedly different 
climates. Thus Primula elatior is confined to the Eastern Counties, while 
Aconitum Napellus, Lithospermum purpureo-ceruleum, Ornithogalum pyre- 
naicum, and Colchicum autumnale, all characteristic of the Somerset woods, 
are rare or absent from the East. 
In the same way the flora of the loam shows a great similarity to the 
Oak Woods of Somerset *. 
Individual Species. 
Primula.—The distribution of the two principal species has already been 
discussed, P. elatior and P. vulgaris hybridize freely f f, and a large 
number of forms have been found in the wood showing all gradations 
between the two parents. The Primrose starts flowering earlier than the 
Oxlip, but reaches its maximum period later and continues longer ; the Oxlip 
flowering season is very restricted. One plant of P. vulgaris was found with 
red flowers, and there was no reason to suppose this was of garden origin ; the 
variety caulescens occurs, and also intermediates between this and the type. 
Besides these two species, Р. veris occurs in small quantity near the edges 
of the wood ; hybrids between this and P. vulgaris occur, but none were noted 
with P. elatior $. P. elatior is the only one of Watson's * Germanie ” || type 
that oecurs in this wood. 
FEpilobium зрр.— уе species of Epilobium | oceur— 72. angustifolium, 
E. hirsutum, Е. parviflorum, Е. montanum, and E. tetragonum. Of these several 
peculiar forms were found that in some ways suggest hybrid origin, but few 
certain hybrids were discovered. 
Populus tremula var. villosa.—The presence of this tree, which is character- 
istic of moist soils, on the loam area in a Dry Oak Wood is of interest as 
being unexpected, The most probable explanation is that the roots are able 
to reach the bottom water, and that the trees here have come in from the 
surrounding moist clay soil. 
* Moss, 1907, р. 54. T Christy, 1897. 1 Bailey, 1903, 
§ Hill, 1907, | Watson, 1847, 
