: 1900 SUPPLEMENT—RECENT INTRODUCTIONS, 
Oncidium—continued. 
the lateral sepals free; lip canary-yellow, with a curious 
crest (resembling vipers’ heads seen in profile); peduncles 
erect, 5in. to 7in. long, few-flowered; axis of the inflorescence 
twining. 7. linear-oblong, 2in. long. Pseudo-bulbs obscurely 
four-angled, lin. long, two-leaved. Uruguay. [T.] 
O. volvox (twining). ji. lin. across; sepals and petals yellow, 
much spotted with reddish-brown for two-thirds of their 
length; lip bright yellow, sub-panduriform ; scapes very 
slender, flexuous, 3ft. to 5ft. long, the branches two- or 
three-flowered. Autumn. J. narrow-ligulate, 8in. to 12in. 
long. Pseudo-bulbs oval-oblong, 2in. to 4in. long, furrowed, 
two-leaved. Caracas, 1854. (R. X. O. i., t. 99, No. 1.) 
©. Warneri (Warner’s). Jl. five to eight in a short raceme; 
sepals oval, spreading; petals narrower and ascending; lip 
bright yellow, three-lobed, flat, the middle lobe deeply parted 
into two roundish lobes. Autumn. J. linear - lanceolate, 
recurved. Pseudo-bulbs ovate, ancipitous, with two leaves. 
Mexico. There are two varieties: purpuratum, sepals and 
petals white, streaked bright purple; and sordidwm, sepals 
and petals dull yellow, streaked purple. [C.] 
©. Widgreni (Widgren’s). i. light yellow, with bars of 
reddish-brown ; co as large as the lip; raceme about 
eight-flowered. /. solitary, 3in. to 4in. long. Brazil, 1889. 
ied to O. cornigerum, but with much brighter-coloured 
flowers. : 
0. xanthocentron (yellow-spurred). #. disposed in a dense 
panicle ; petals hastate, having a dark spot over the base; lip 
dark, with a rhomboid, yellow centre. Andes. The contrast 
of colours in this species is very marked. 
0. zonatum (zoned). #. variable in form; 
petals yellow, with tranverse, brown bands. 
Allied to 0. bryolophotum. 
Large numbers of species not enumerated are also grown in 
botanical establishments, including: O. abortivum, 0. iridifolium 
(of Humboldt), 0. ogthostates, O. pictum, O. Schillerianum, O. tri- 
odes, O. Trulia. 
sepals white ; 
Colombia, 1893. 
Fic. 601. ONCIDIUM MARSHALLIANO-FORBESII. 
Natural Hybrids. 
PARENTAGE. 
Syn. O. Marshalliano-Forbesii. 
Syn. 0. Gardneri. 
NAME. 
CAlOglOssUuM ...0-eeeeeee 
elegantissimum .....+-+ 
elliferum .......... Syn. O. Gardneri. 
Gardneré ........00 «++. Forbesit and dasystyle. 
hematochilum ........ luridwm and Lanceanum. 
Larkinianum.......... Syn. Marshalliano-Forbesii. 
ee pitaicise sls ors Syn. Marshalliano-Forbesii. 
a Tie 601) eo orberts } Marshattianum an Forbesii. 
SOLOTOIA Wem de cm sre deine .. Syn. Marshalliano-Forbesii. 
Pollettianum ....+++... Syn. Gardneri. 
preestans ...... seseeeee Syn. Gardneri. 
preetextum ......+ «eee. Syn. Gardneri. 
Wheatleyanum ........ crispum and dasystyle. 
ONCOMA. A synonym of Oxera (which see). 
ONCORRHYNCHUS. A synonym of Orthocarpus 
(which see), 
&C. 567 
ONCOSPERMA. 0. tigillaria is grown at Kew, 
but it is not in general cultivation. 
ONE-SHIFT SYSTEM OF POTTING. [his 
consists in moying a plant from the cutting-pot, or 
from the pot into which it was put as a seedling, into 
that in which it is intended to blossom or fruit. Soft- 
wooded plants—such as Pelargoniums—succeed very well 
on this system when potted on from a 3in. pot to one 
6in. or more across. Tomatoes, again, answer very well 
on this system, but extra care in watering is necessary 
until the pots are filling with roots, otherwise the soil 
becomes sour and the plants unhealthy. Hard-wooded 
plants do not succeed well on the One-Shift System. 
ONION. Besides the pests already described in 
connection with the Onion, there is one which promises 
to be more destructive than any yet recorded. This is a 
species of Nematoid Worm (which see, Vol. II.), now 
popularly called EKelworm. The species, Tylenchus 
devastatrix, does not confine its attention to one plant, 
but is found upon many, from Cloyer to Hyacinths. 
The symptoms of attack are chiefly a swelling of the 
infested bulbs, followed by a cracking; while the foliage 
is frequently distorted as well. The bulb, though ap- 
parently sound to the eye, nevertheless when handled is 
flabby, if not soft unto rottenness. 
Once the disease asserts itself, it is difficult, if not 
impossible, to combat. All infested bulbs should be care- 
fully lifted and burned. On no account should the same 
quarters be used for a similar crop the next season. As, too, 
the Nematoids may be present in the seed, care should 
be taken not to utilise any from an infested garden. 
On the Continent the disease known as Onion Sickness 
is far more prevalent than here; but considering the 
quantities of seed obtained in this country from Conti- 
nental establishments, it is easy to conceive how readily 
disease may be introduced into what was previously a 
perfectly healthy area. 
The Welsh or Spring Onion, or Ciboul (Alliwm fistulosum), 
is cultivated the same as the ordinary variety, except 
that very little thinning is necessary, as the plants do 
not form bulbs. Though very hardy, the plants are of 
little value, and scarcely worth growing. 
The following are all good additions to the varieties of 
Onions : 
A 1. Bulbs large, deep, round, with a medium neck; skin 
brownish-yellow; flesh whitish, firm. An excellent keeper. 
Valuable alike for autumn or spring sowing. 
Ailsa Craig. Bulbs very large, roundish, with a small neck ; 
skin greenish-white; flesh very solid. This is probably the 
largest variety, and it keeps well. In 1895, Mr. J. Bowerman 
exhibited twelve Onions of this variety weighing 3741b. ; while 
single bulbs have been grown weighing 3lb. 940z. 
Cranston’s Excelsior. An excellent variety, and very 
similar to Ailsa Craig in size and appearance. 
Crimson Globe. Bulbs medium, globular; skin glossy 
crimson. A fine variety for spring sowing, and a good keeper. 
Giant Zittau. Bulbs round; skin deep yellow; flesh firm. 
A long keeper. One of the best for autumn sowing. 
Silver Globe. Bulbs medium, globular; flesh firm, 
the mildest-flavoured varieties. 
distinct from White Globe. 
ONION SICKNESS. See under Onion. 
ONOBRYCHIS. To the species described on p. 496, 
Vol. II., the following should be added: 
©. laconica (Mount Laconia). fl. bright pink, large, disposed 
in a dense, oblong-cylindrical spike; peduncles very long. 
Summer. /., leaflets seven to nine pairs, elliptic-linear. Orient, 
1892. Plant stemless (or stem lft. high), silky-canescent. 
O. vicizefolia (Vicia-leaved). According to the Kew authorities, 
this is the correct name of O. sativa. 
ONOCLEA. These plants require an abundance of 
water at the roots all the year round, and are best adapted 
for planting out in the hardy rockery or Fernery, as pots 
scarcely afford them sufficient accommodation for the full 
development of their rhizomes or stolons, which, in some 
instances, extend a very long distance. The soil which 
Onocleas prefer is a compost of three parts good 
strong loam and one of leaf-mould. reat care should 
be taken that at all times of the year their roots are 
kept in a damp state. Some magnificently cultivated 
examples of these Ferns exist at the Botanic Gardens, 
Cambridge, where Mr. R. I. Lynch has had the good idea 
One of 
An excellent cropper, and 
