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Digby . — The Cytology of Primula kewensis 
The buds have been fixed in strong Flemming, Hermann, alcohol and 
acetic, strong and medium chromo-acetic, and Merkel. Fixations have 
been made between n a.m. and 12.30 p.m. on bright warm days. Under 
these conditions plentiful nuclear divisions have been obtained. 
It is found that the nuclei of many of the buds are in the state of rest 
which intervenes between the last premeiotic and the first meiotic division. 
This stage must be one of long duration, for during its period the whole 
bud grows considerably. There is again a resting stage during synapsis, 
for it is not unusual to find all the five anthers of a bud with their pollen 
mother-nuclei in close synapsis. From the coming out of synapsis to the 
completion of the homotype division the sequence of the nuclear phases is 
extraordinarily rapid. Often, in the microscope field of a transverse section 
of a bud, the nuclei of the youngest loculus will be in £ hollow spireme 
whilst those of the oldest loculus will have already passed through the two 
meiotic divisions and be in the tetrad stage. The two outer loculi of an 
anther are always in advance of the inner two, and one loculus in each 
respective pair is slightly ahead of the other in the progress of nuclear 
division. Moreover, there is a great difference in the stages between the 
pollen mother-nuclei near the top of a given anther and those near the base 
of the same anther, so that by following the sequence of the sections of an 
anther cut transversely a perfect gradation can be obtained. 
A variety of stains has been used, including Heidenhain’s iron-alum 
haematoxylin with a counter stain ; Flemming’s triple ; Breinl ; methylene 
blue and eosin ; gentian violet and orange G, &c. 
Horticultural History. 
It is well known that certain Primulas are not difficult to cross 
artificially, and occasionally accidental hybrids have arisen, and to this class 
belongs Primula kewensis (13 and 14 ). P . floribunda and P. verticillata 
were grown in quantities at Kew, and when in flower were constantly 
placed near to one another. In 1899 Mr. F. Garrett, the foreman, noticed 
in a pan of presumably pure P. floribunda seedlings one which was 
stronger in growth and different in foliage to the others. When it flowered 
it was evident that it was a hybrid, for it possessed the combined characters 
of P . floribunda and P. verticillata. It inherited from P . floribunda its con- 
tinuous flowering nature, the colour of its flowers, and the shape of its 
leaves, and from P. verticillata its size, the length of its leaf-stalks, its 
foliaceous bracts, the character of its flowers, and the traces of mealiness on 
the corolla tube, on the upper part of the calyx, and on the leaves. The 
feature of mealiness is a most pronounced characteristic of P. verticillata. 
This hybrid plant, Pidmula kewensis (type form), was exhibited at the 
Meeting of the Royal Horticultural Society on February 27, 1900, and was 
awarded a First Class Certificate. 
