866 
the gardening world, 
August 27, 1904. 
If large specimen plants are grown, see that they are well 
staked out, so as to let light and air into them. Keep a sharp 
lookout for rust and mildew. Plants that are affected must 
be removed and kept in a batch by themselves for special treat¬ 
ment. Earwigs are often troublesome, but a good plan, to 
catch them is to fill small pots with brown paper and invert 
them on top 1 of stakes among the plants. This forms a sure 
trap 1 for them, from whence they can be shaken out and trod 
on, looking after them as often, as possible. 
Disbudding should be attended to closely. It is a, waste of 
strength to allow lateral growth to extend unduly; study the 
different varieties asi to whether the first, second or third 
crown-bud will be the best to save; the second is the one 
usually chosen, though the third or terminal in most cases 
comes the best colour. 
Get, the plants housed as fast as the buds begin, to show 
colour, leaving the house wide open night and day at first. 
Should damp weather prevail, just warm the pipes; later on^ 
as the flowers, expand, a little more warmth may be needed, 
keeping a, temperature of 50 to 55 deg. with 
a good circulation of air. When the flowers 
are fully expanded give water sparingly, for 
nothing brings damp- among the flowers more 
than over-watering at this stage. H. W. 
that is to say, that hand pollinating did not. take 
place, but two' specie® growing side by side crossed, the pro¬ 
bable parents being P. floribunda- and verticillata. This 
hybrid; that is to say, that hand pollinating did not take 
duce fertile seed. Supposing that this cross had taken place 
in the wild state of nature, how then would it have fared 1 ? 
Seeing that it is unable to reproduce itself sexually, and to 
propagate by offshoots isi a very slow process. The degree of 
sterility of hybrids is a point to which Darwin pays special 
attention, but a point worth noting with regard to P. kewense 
is that only the “ pin-eyed” form exists, at least so far as my 
observation goes, and I have carefully examined the whole 
stock in the nursery from which it was introduced. 
Mide hybrids are by no means uncommon ; whereas there 
are oases in which true hybridsi are quite fertile, capable of 
reproducing themselves quite as freely as either of their 
parents. 
The view has been entertained by naturalists that species 
when intercrossed have been specially endowed with sterility 
The Primrose and Darwinism. 
(i Continued from page 663.) 
In my first article on this subject, I made 
mention of some experiments on the fertilisa¬ 
tion of Primula obeomicai. These experiments, 
which were given in tabulated form, are 
strongly in favour with Darwin’s views on, the 
subject of heiterostylism. True it is that P. 
oboonica is a distinct species from P. vul- 
craris, the common Primrose, but still the 
flowers are precisely .similar with regard to 
their dim orphic character. The author of 
“ The Primrose and Darwinism ” is greatly 
opposed to Darwin’s views, and indicates that 
the nature of the two. forms is similar, and 
that they are merely, though persistent, 
varieties. 
It, isi obvious that the “ thrum-eyed ” 
varieties are more difficult to. hand pollinate 
than the “ pin-eyed ” varieties. Supposing 
large batch of Primula® (single) which were 
ducinig seed, undoubtedly the best method 
one. 
had a 
shy in pro¬ 
to 1 pollinate 
would be to make all the “ pin-eyed ” plants seed bearers and 
use “ thrum-eyed” plants as* pollen: hearers:. If “ thrum-eyed ” 
varieties were made seed, bearers, it not only mean® that its 
corolla tube must, be split to reach, the pistil, but, also, that of 
the “ pin-eyed ” variety to obtain: pollen—that isi, if one were 
to work according to Darwin's views, which I 'have good reason 
to believe are correct. I have noticed that “ pin-eyed ” 
varieties, have a, great tendency when used as seed: hearers to 
reproduce plants of “ pin-eyed ” form, and this, may account 
for the remark made by a “ G.W.” correspondent when visiting 
a large nursery where Primulas were grown by the thousand, 
that the “ pin-eyed ” varieties 1 greatly predominate. 
The Oxlip, P. elatior, which is a native of our woodlands, 
isi an intermediate form between, the Primrose and the Cow¬ 
slip 1 , P. officinalis;; it is particularly interesting since it ha® 
been known do produce both “pin-eyed” and “ thrum-eyed ” 
varieties on one root. So far as I am aware, this, is the only 
case recorded. 
Hybrid Primula® are by not means common, but quite re¬ 
cently a beautiful hybrid ha® been, introduced—namely, P. 
kewense. This hybrid ha® been figured in the “ G.W.” and 
details of its cultivation given. P. kewense is interesting as 
well as beautiful : it originated at Kew as an accidental garden 
Hypericum poylphyllum. (See p. 683.) 
in order to prevent their confusion. This, however, has been 
proved to be incorrect, .and Darwin refers to the degree of 
sterility as an, incidental result of differences in the repro¬ 
ductive systems of the parent species. The great naturalist 
doe® not admit that this in, any way interferes with his great 
theory of natural selection, for in “ The Origin of Species ” he 
states that “ we have conclusive evidence that the sterility of 
crosised specie® isi due to a principle quite independent of 
natural selection.” 
No> one is able to explain the unequal fertility of reciprocal 
.crosses; thus, for example, in, my experiments “ pin-eyed ” x 
“ thrum-eyed ” produced more fertile seed than ‘ thrum-eyed ” 
x “ pin-eyed,” the seed-bearing parent being mentioned first 
in each case. Herbert Cowley. 
The Oyster Plant in Orkney.— The “ Orkney Herald ” re¬ 
cords the fact that a strange plant was found at Hennibister 
Firth, and sent to Mr. E. Holmes for determination. This 
gentleman recognised it as the Oyster Plant (Martensia mari- 
tima), and says he has only gathered it twice, once at Holy 
Island, Northumberland, and once near Arbroath. We have 
at least one other station for it. Our contemporary is in error, 
however, in stating that Mr. Holmes is superintendent of Kew 
Gardens. Mr. Edward Morell Holmes, if that is the gentle¬ 
man intended, is, curator'of the, Museum of the 'Pharmaceutical 
Society. 
