AN ENCYCLOPADIA OF HORTICULTURE. 
Sirex—continued. 
passed through in a few weeks; but the perfect insects 
have emerged at intervals for many years from wood 
to which the larve could not have got access after the 
trees had been felled and sawn into planks. The larve 
have strong jaws, six very small feet near the head, 
and a bluntly-pointed tail. They change in their tunnels 
into pups. From these the perfect insects emerge, from 
July to September, 
S. juvencus, or the “ Steel-blue Sirex,” is, as the name 
denotes, usually of a dark steel-blue colour, with red- 
brown feet ; in the males, several segments of the abdomen 
are rusty-red. The wings, in both sexes, are yellowish, 
with smoky hind margin. The females are usually 1jin. 
long, the males rather below lin. This insect is not rare. 
It prefers Scotch Firs, though it also feeds in other 
Conifers, 
S. gigas, or the Giant Sirex, is rather larger than the 
other species, from which it also differs in colour. It is 
ringed with black and yellow; the latter colour is duller 
in the males. This species is less common than the 
former. The larve are said not to attack Scotch Firs; 
but feed in Spruce, Silver Firs, and occasionally in Larch. 
Remedies. It is not possible to destroy the larvæ in 
infested trees. To prevent the injury from spreading, 
sickly trees, and all fallen branches and trunks, should 
be cut up and removed; and this should be done also with 
all trees that show traces of serious injury, in the form 
of holes through which the insects have escaped. The 
timber of such trees is of little value, save as firewood, 
because of the injury done to it by the larve. 
SIRIUM. A synonym of Santalum (which see). 
- SISARUM. Included under Pimpinella. 
SISSOO-TREE. A common name for Dalbergia 
Sissoo. 
SISYMBRIUM (an old Greek name, used by Theo- 
phrastus for Mint). Hedge Mustard. Including Alliaria. 
ORD. Crucifere. A genus comprising eighty species of 
hardy, mostly annual or biennial herbs, usually inhabiting 
the temperate and cold regions of the Northern hemi- 
sphere, but rarely occurring in the Southern. Flowers 
usually yellow, rarely white or rose, loosely racemose, 
rarely axillary Radical leaves stellate; cauline ones 
alternate, Five species are included in the British 
Flora: §S. Alliaria (Garlic Mustard, Jack-by-the-Hedge, 
Sauce Alone), S. Ivio (London Rocket, so called because 
it sprang up after the Great Fire), S. oficinale (Bank 
Cress, common Hedge Mustard), S. Sophia (Flixweed), 
and 8. Thaliana (Thale Cress). The genus has no horti- 
cultural value. . 
 SISYRINCHIUM (an old Greek name, used by Theo- 
phrastus for the Iris). Blue-eyed Grass ; Pig Root; Rush 
Lily; Satin Flower. Syn. Souza. Some of the plants 
included here were formerly placed under Bobartia. ORD. 
Irideæ. A genus comprising about fifty species of mostly 
hardy or half-hardy perennials, with fibrous roots; all 
are natives of tropical or extra-tropical America, and 
one has become naturalised in Ireland. Flowers many 
in a spathe, pedicellate ; perianth with scarcely any tube, 
and sub-equal, obovate or oblong lobes; stamens affixed 
at the base of the perianth. Leaves radical or clustered 
at the base of the stem, linear-terete or more or less ensi- 
form, always narrow ; cauline ones few or none. Stems 
equal or slightly thickened at base. A selection of the 
Species best known in gardens is given below. All 
thrive in a compost of sandy loam and leaf mould. 
Propagation may be effected by seeds, or by offsets, in 
spring. _ 
S, anceps (two-headed). A synonym of S. angustifolium. 
S. angustifolium (narrow-leaved). . of a paler blue than in 
S. Bermudiana. I. narrower, and whole plant smaller. Eastern 
United States (naturalised in New Zealand and Australia, also 
in Ireland). Syns. S. anceps, S. gramineum (B. M. 464). 
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Sisyrinchium—continued. 
S. Bermudiana (Bermudan). This differs from S. angustifolium 
in being much arer in all its parts, and strikingly so in its 
broad leaves, which are equitant at the base. h. lft. to 2ft. 
„_ Bermudas. SYN. S. iridioides (B. M. 94). 
S. californicum (Californian). /t. many in succession, scentless ; 
perianth of a uniform yellow, explanate, the segments obovate- 
oblong, obtuse; anthers orange-coloured ; fascicle many-fiowered ; 
scape quite simple, longer than the leaves, curved. Autumn. 
l. several, distichous, lft. to nearly 2ft. high, about jin. broad, 
linear-ensiform. California, 1796. Half-hardy. Sys. Marica 
californica (B. M. 983). 
S. chilense (Chilian). fl., :perianth purple, yellow at the base, 
three to five lines long ; bracts leaf-like ; spathe linear, acuminate, 
about three-flowered ; peduncles flexuous, very slender, lin. to 
ljin. long. July. l, radical ones linear-ensiform, striated, Sin. 
to 12in. oe one to two lines broad. Stem 6in. to 12in. high, 
flexuous. Brazil, &e., 1826. Half-hardy. (B. M. 2786.) 
S. Douglasii (Douglas’). A synonym of S. grandiflorum. 
S. filifolium (thread-leaved).* /. campanulate, erect; perianth 
white, like porcelain, each segment delicately lined with i 
urplish-red. May. h., 6in. to 8in. Falkland Islands, 1885. 
lant of Rush-like habit. (B M. 6829; G. C. n. s., xxiii. p. 696.) 
S. gramineum (grass-like). A synonym of S. angustifolium., 
graminifolium (grass-leaved), slightly exserted above the 
spathe; perianth yellow, the segments obovate, mucronate ; 
spathes terminal, few or many-flowered, the outer one leafy, Lyin, 
long, the inner lin. long. April. Z., radi ones Bin. long, 
scabrous on the margins, acuminate, sheathing at base ; ine 
ones 3in. to 6in. long. Stem branched, erect, Tin. to 9in. high, 
Chili, 1825. Half-hardy. (B. R. 1067.) f 
S. g. ascendens (ascending). f., spathes very hairy, eq 
pg eo ones 4in. to cin, Tong ; cauline ones 2in. to din. I 
alternate. Stem 5in. to 9in. high. (B. R. 1914, under name o! 
S. g. pumilum.) X 
tum (spotted). 
ñ., perianth segments marked ‘with 
S. g. macula’ 
per EE spots. (B. M. 3197, under name of S. macu- 
tum. 
gran orum e-flowered).* Spring Bell. fl., perianth 
E 8 hg or o x te, un Fie , eight 
dark purple, stria 
to ten lit 
two-valved. May. 
6in. to 8in. long, sheathin, 
simple. Root creeping. North America, 1826. A pretty hard 
pe See Fig. 490. (B. M. 3509; B. R. at Fs E n. S., XXi. 
216; R + as F. G. ser. ii. 388.) SYN. 
; ee a a S. B. : _ 388 r 
y Douglasii (F. d. S. 146). There is a variety of this with white 
flowers. 
S. iridifolium (Iris-leaved).* /. on slender pedicels, pubescent 
beneath ; perianth yellowish-white, the segments about šin, long, 
cuneate-ligulate, slightly mucronate ; spathes terminal, the outer 
one lżin., the inner lin., long, carinate; peduncles geniculate. 
June. l. linear-ensiform, incurved at apex, on 
the margins; radical ones ĝin. to 8in. long; cauline ones 2in. to 
