522 
JOURNAL OF HORIICULTURE AND COTTAGE GARDENER. 
December 11, 1884. 
the top spit. Any rubbish is good enough for the bottom, but 
the best short manure shou'd be reserved for the top. 
Now supposing trenching has been well and intelligently 
carried out, it yet remains to be proved that this greatly 
deepened root-run will prove so very advantageous to the 
majority of crops occupying the ground. Is it not a fact that 
a deep and. in this case, loose soil results more often than not 
in the production of a much greater amount of haulm or leaves, 
as the case may be ? If this greater luxuriance were followed 
by a correspondingly greatly increased yield, the gain would 
be evident enough, but as it happens the revei’se is most fre¬ 
quently the case. Take Strawberries for instance, will these 
yield well if given to over-luxuriance ? No trenched ground 
I have yet seen has produced such heavy crops of fine fruit to 
equal those annually grown on ploughed land only. It is just 
the same with any kind of fruiting plant. Keep them rooting 
near the surface, this being done by avoiding digging and apply¬ 
ing frequent manurings and mulchings when necessary, and they 
are certain to form moderate growth and plenty of fruiting 
wood. Broccolis and other members of the Brassica family grow 
most luxuriantly on deep loose ground without producing any 
better, and, at the same time, being more liable to be destroyed 
by frosts. Beans and Peas form more haulm than is wanted 
without surpassing others of the same nature on ground re¬ 
ceiving good surface treatment; and even Asparagus, which is 
supposed to require deeply trenched ground and other formulas, 
does equally well on well-drained ground, manured, and dug 
similarly to the preparation made for other crops. The Asparagus 
is especially a surface-rooting plant, as anyone will see who 
may lift some of the roots, and we had far better encourage them 
on the surface rather than entice them downwards. What I 
have found to do well on trenched ground are Celery and Potatoes, 
and in both cases the reason is not far to seek — the Celery 
rooted out and away from the trench, while the Potatoes were 
better simply because the ground cannot well be too loose or 
broken up for them.—W. Iggulden’. 
MRS. PINCE GRAPE. 
Tour correspondent ‘ Tilch” (on page 483) appears to be rather 
dubious about this Giapc as a late keeper. I have fouud it in this respect 
quite equal to Lady Dawne’.->, liaving cut the bunches of Mrs. Pince for 
years in succession a week or so before pruning the Vines in February as 
plump as could be desired, the fruit being then bottled in the usual way. 
This Grape is a'so superior in flavour t) that of Lady Downe’s, besides 
having the by no means to be despised property (in all seasons) of bearing 
a full crop in houses where from three to six different varieties are 
pilanted, and undoubtedly it is oftener grown under those circumstances 
than in a vinery devoted to itself. Your correspondent asks if I keep on 
a little ventilation at all seasons. We admit air at all times when the 
temperature outside will allow. As regards our Vine roots, the Vine 
borders here, both out and inside, are a complete network of active roots 
within a few inches of the surface —J. J. 
THE DARWIN POTATO—SOLANUM MAGLIA. 
On January 17th of the present year Mr. J. G. Baker of Kew read 
before the Linnean Society an exhaustive aud interesting paper upon 
tuber-bearing Solanums, in which the several species possessing this 
character were described, v'^pecial reference was made to S. Maglia as 
being from a humid climate, and therefore worthy of the attention of 
hybridists. The subject is an important one, and, with a view to testmg 
its disease-resisting powers, w'e obtained some tubers of this species, 
together vith lome of S. Jamesii. These were both treated alike — 
namely, were grown in pots in a well-ventilated frame and received all 
necessary attention. S. Maglia made very slow progress at first, but 
ultimately produced a strong well-developed haulm, which appeared per¬ 
fectly heabhy until late in the au'umn, when it was attacked by a fungus 
which rapidly spread over it. The few tubers produced do not, however, 
seem to be affected. S. Jamesii was similarly attacked, and in this case 
the lubers also had a diseased appearance. In a season exceptionally 
unfavourable to the ordinary form of the Po'ato disease this was the more 
remarkable, and to remove any doubt about the matter we submitted the 
haulm of S. Maglia and the tube s of S. Jamesii to Mr. Worthington G. 
Smith, who giv'es the following remarks as the result of h's examination :— 
*■ No doubt you will publish a descrip ion of the diseased plants of 
Solanum Maglia, one of which you have sent on to me. My plant, 
although alive, is in a bad state, the leaves being d scoloured and withered, 
as if they had been placed in some poisonous solution; a very few bright 
patches of green, however, remain here and there. The main stem and 
leafstalks are also diseased. A search over the entire plant has failed to 
detect the Potato fungus named I’eronospora infestans, although other 
fungi are present. On examining the leaves under the microscope fungus 
spawn is in every instance readily fouud growing within the leaf. In 
every part of the stem, as well as in the leafstalks, similar spawn is met 
with. In several places the stems and leafstalks are soft. On cutting 
the soft places open the whole interior is fouud to be one felted mass of 
fungus spawn or mycelium. The bad condi'ion of the leaves is un¬ 
doubtedly caused by this profuse mycelium inside the stem, the leaves 
being virtually disconnected from their supporting stalks and the main 
stem. 
“ The mycelium does not remind me of Peronospora infestans, but of 
the fungus which has of late been so extremely destructive to Potatoes 
in Ireland—viz., Peziza postuma. The effects in both instances are the 
same. In Solanum Maglia the mycelium is not yet far enough advanced 
in growth for the jiroduction of the compacted spawn masses termed 
Sclerotia. Whatever the disease is, the plant of Solanum Maglia is 
traversed throughout, and in some places the tissues entirely destroyed, 
by fungus spawn. 
“ Too much has been made of the supposed immunity of Solanum 
Maglia from disease; there is no reason to suppose it able to resist 
disease. Mr. Baker considers it to be a distinct species from S. tuberosum, 
and so hybrids may be useful and experiments should be made and en¬ 
couraged. Mr. Baker has clearly pointed out that whilst S. tuberosum is 
a plant of the interior hills of Chili, S. Maglia grows in the near neigh¬ 
bourhood of the coast. He therefore thinks that the native habitat of 
the latter more accords with the climate of Britain than the former, and 
that S. Maglia may grow here in a more healthy manner than does S. 
tuberosum. 
“ Nothing more can be said. The speculations as to S. Maglia being 
disease-proof are of little value, for it is known to be one of the species 
on which the Peronospora grows. Suppose our climate does suit S. 
Maglia, it is very certain that it suits the Peronospora too, and the 
Peronospora invades healthy plants, not sickly ones. We have in Solanum 
Maglia a plant from a humid region of Chili, and it appears to fall before 
a fungus M’hich is possibly the same with the one which has been ex¬ 
tremely destructive in a humid country like Ireland. I hope Solanum 
Maglia will do well in Britain—perhaps it may, there is a fair chance ; 
but it is necessary to warn gardeners against much that has been written 
(not by Mr. Baker) about its disease-proof qualities. I have examined 
the diseased tubers of Solanum Jamesii; the disease patches appear to 
arise from a form of scabbing. No trace of Peronospora infestans was 
met with, but the mycelium of some other fungus was common. The 
tubers are in a bad state, the brown mottling in some instances going a 
considerable depth into the substance of the tuber.” 
In connection with this subject Mr. Baker’s observations upon S. 
Maglia may be advantageously reproduced •.— 
“ From all that we know it would appear that in Chili S. tuberosum is 
a plant of the hills of the interior, S. Maglia of the near neighbourhood 
of the coast. This is still further confirmed by the fact that the wild 
Potato found by Darwin in the Chonos Archipelago, in south latitude 
44 °- 45 °, undoubtedly conspecific with the S. Maglia of Valparaiso. 
Original specimens from Darwin are in the Kew herbarium, and they are 
quite characteristic of S. Maglia, differing only from the plant grown in 
Kew Gardens just described by their larger (white) corolla and more 
densely hispid calyx, with more acute teeth. Darwin’s note on the plant, 
as printed at page 288 of the 1835 octavo edition of the ‘ Voyage of the 
Beagle,’ is as follows:—‘ Cbonos Archipelago.—The wild Potato grows on 
the islands in great abundance on the sandy shelly soil near the sea- 
beach. The tallest plant was 4 feet in height. The tubers were gene¬ 
rally small; but I found one of an oval shape 2 inches in diameter. They 
resembled in every respect and had the same smell as English Potatoes ; 
but w'hen boiled they shrunk much and were watery and insipid, without 
any bitter taste. They are undoubtedly here indigenous. They grow as 
far south, according to Mr. Low, as latitude 50°, and are called Aquinas 
by the wild Indians of that part. The Chilotan Indians have a different 
name for them. Professor Henslow, who has examined the wild speci¬ 
mens which I brought home, says they are the same with those described 
by Mr. Sabine from Valparaiso ; but they form a variety which by some 
botanists has been considered as specifically distinct. It is remarkable 
that the same plant should be found on the sterile mountains of Central 
Chili, where a drop of rain does not fall for more than six months, and 
within the damp forests of these southern islands.’ The true explanation 
of what Darwin in the last sentence, with characteristic sagacity, com¬ 
mented upon as very remarkable, is evidently that the Chonos plant and 
that of the Chilian Cordilleras are each distinct species. 
“ The plant dealt with by Sabine in his well-known paper ‘On the 
Native Country of the Wild Potato,’ in the fifth volume of the ‘ Transac¬ 
tions of the Horticultural Society,’ is also undoubted Solanum Maglia, as 
just described. The history of the plant is as follows :—Two tubers 
were sent to the Society from Chili in 1822 by Mr. Alexander Caldcleugh, 
Secretary to the Legation at Rio Janeiro. They were planted in the gar¬ 
den at Chiswick in richly manured soil, and the produce was most abun¬ 
dant. The two plants in a single season yielded about six hundred tubers. 
These were of vaidous sizes, a few as large or larger than a pigeon’s egg, 
others as small as the original wild ones, which were globose and under 
an inch in diameter. The flavour of them when boiled was exactly that 
of a young cultivated Potato. Sabine gives two excellent figures, a 
coloured one of the stem, leaves, and flowers, life-size, on plate 11, and 
on plate 9 figures of two tubers before and after cultivation. Although 
these figures are c ted by Dunal in his Monograph in Da Candolle’s 
‘ Prodromus ’ under S. tuberosum, there cannot be any doubt that they 
represent excellently the present type.” 
Mr. Aithur W. ISutton of Reading has also been making some investi¬ 
gations into the characters and probable value of these species, and the 
following letters in reference to the su'^ject appeared in the Times of 
November 29th ;— 
“ Lord Cathcart has suggested that you would probably consider the 
facts mentioned in the enclosed letter of general interest. 
