Arthur W. Mill. 
166 
It is, of course, impossible to say whether the hybrid just 
described is a first cross between an Oxlip and a Cowslip or not, 
though the evidence seems to be in favour of this view. Its 
characters are more or less intermediate between those of the two 
parents, though the influence of the Oxlip appears to to be somewhat 
the stronger. In general hairiness, shape, and markings of the 
flower, and scent, as well as in the internal structure of its 
flower-scape, the Oxlip characteristics are predominant, whilst in 
the shape, position, and appearance of the leaves, and in the 
orange colour of the flowers, the influence of the Cowslip is clearly 
seen. 1 
The hybrids between the three species of Primula in Britain 
are of such interest that it is to be hoped that they will soon be 
subjected to careful scientific experiment. There can be no doubt 
that inter-crossing experiments will yield results not only of 
considerable interest as to the various forms found in a wild state, 
but will also throw important light on questions of hybridisation in 
general. 
EXPLANATION OF PLATE V. ILLUSTRATING MR. A. W. HILL’S 
PAPER ON THE NATURAL HYBRID BETWEEN THE COWSLIP AND 
OXLIP. 
Fig. 1. The Cowslip x Oxlip hybrid, P. officinalis x elatior ; shewing the 
Cowslip-like leaves and the flowers and flower-scape more like those of 
the Oxlip, cf Fig. 6. The corolla is orange, and the calyx shews Cowslip 
characters. 
Fig. 2. An umbel and leaf of the true Oxlip, P. elatior L , cf. F'ig. 5. The 
corolla is of a pale cream colour with an orange ring. The calyx is 
contracted at the throat. 
F'ig. 3. An umbel and leaf of the Cowslip, P. officinalis, L , cf. Fig. 7. The 
corolla is deep orange with characteristic markings and the loose calyx 
has short blunt teeth. 
Fig. 4. An umbel and leaf of the hybrid Cowslip x Primrose, P. officinalis x 
acaulis, cf Fig. 8. Note the wrinkled leaf and hairy flower-scape. The 
corolla is yellow, with the five spots of the Cowslip shewing on the star- 
like eye of the Primrose. The calyx is inflated and hairy. 
F'igs. 5—8 for a comparison of the floral characteristics of these four plants. 
Fig. 5. Flowers of the Oxlip. 
F'ig. fi. The Cowslip x Oxlip. 
F'ig. 7. The Cowslip. 
F'ig. 8. The Cowslip x Primrose. 
The photographs were taken by Mr. Allard Foreman of the Botanic 
Garden, Cambridge. 
1 Owing to the innumerable gradations between the Oxlip and the 
Primrose, which are found as natural hybrids, it is not 
possible at present to discuss the influence of each of the 
parents in the first cross. 
