I 6 2 
Arthur W. Hill 
THE NATURAL HYBRID BETWEEN THE COWSLIP 
AND OXLIP, 
By Arthur W. Hill, M.A. 
[With Plate V. and Text-Figs. 5 and 6.] 
NE of the most interesting features of the flora of the country 
around Cambridge is the occurrence of the true Oxlip r 
Primula elatior L.—Jacquin’s or the Bardfield Oxlip—in certain 
areas of woodland on the boulder clay, and the absence of the 
Primrose P. acaulis L. from such woods as are well within the 
Oxlip area. 
The exact distribution of the Oxlip has been so beautifully 
worked out by Miller Christy 1 that it would be superfluous to enter 
into the question in any further detail in this brief note. Suffice it 
to say that the main Oxlip area occupies an irregular tract of 
country on the borders of Cambridgeshire, Essex and Suffolk, with 
large extensions into Suffolk and Essex; whilst there is a small 
triangular area to the west of Cambridge, roughly bisected by the old 
North Road. In addition to this there are two small outliers, one 
in the neighbourhood of Great Livermere to the north of Bury St. 
Edmunds, and the other near Diss, in Norfolk. The primrose 
occurs round the margins of these areas, and, as is well known,, 
hybridises freely with the Oxlip. There seems little reason to doubt 
that the restricted and peculiarly outlined habitat of the Oxlip in 
England is due to the fact that it is being gradually ousted by the 
more successful Primrose. 
On the Continent the Oxlip appears to have as extensive a 
range as both Primrose and Cowslip (P. officinalis L.), being found 
all over Western and Central Europe, from Holland and France to 
S. Russia and from S. Sweden and Denmark to the Northern Alps. 
Although the Primrose and Oxlip appear to be mutually 
exclusive in England, the Cowslip, on the other hand, grows freely 
throughout the Oxlip country, but hybrids between the two species 
are very uncommon. A few records of the cross elatior x offici¬ 
nalis aregiven by Pax- and are sometimes known as P. media ; and 
Christy 3 mentions the finding of three probable Cowslip x Oxlip 
hybrids during the last eighteen years. The rarity of this cross is 
1 Miller Christy. P. elatior in Britain, Journ. Linn. Soc. XXXIII., 
p. 172, with map. 
Bailey. Journ. Bot., XLI., p. 145. 
2 Pax & Knuth. Pflanzenreich ; Primulacea:, pp. 60, 61. 
* Miller Christy, l.c., pp. 197, 198. 
