AN ENCYCLOPAEDIA OF HORTICULTURE. 



439 



Sir ez continued. 



passed through in a few weeks ; but the perfect insects 

 have emerged at intervals for many years from wood 

 to which the larva; could not have got access after the 

 trees had been felled and sawn into planks. The larvae 

 have strong jaws, six very small feet near the head, 

 and a bluntly-pointed tail. They change in their tunnels 

 into pupae. From these the perfect insects emerge, from 

 July to September. 



8. 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 l^in. 

 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 hitter colour is duller 

 in the males. This species is less common than the 

 former. The larvae 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 larvae 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 larvse. 



SIEJUM. A synonym of Santalum (which nee). 

 SISARTJM. Included under PimpineUa. 

 SISSOO-TBiEE. A common name for Dalbergia 

 Sissoo. 



SISYMBBTUM (an old Greek name, used by Theo- 

 phrastns for Mint). Hedge Mustard. Including Alliaria. 

 ORD. Cruciferce. 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 : 8. Alliaria (Garlic Mustard, Jack-by-the-Hedge, 

 Sauce Alone), 8. Irio (London Socket, so called because 

 it sprang up after the Great Fire), 8. officinale (Bank 

 Cress, common Hedge Mustard), 8. Sophia (Flixweed), 

 and 8. ThaUana (Thale Cress). The genus has no horti- 

 cultural value. 



SISYRINCHIUM (an old Greek name, used by Theo- 

 phrastns for the Iris). Blue-eyed Grass ; Pig Boot ; Bush 

 My; Satin Flower. STN. Souza. Some of the plants 

 included here were formerly placed under Bobartia. ORD. 

 Irideai A genus comprising about fifty species of mostly 

 hardy or half-hardy perennials, with fibrous rcots; 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- 

 fonn, 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 of sets, in 

 spring. 

 S. anceps (two-headed). A synonym of S. anguttifoKum. 



^fSSSSSSTi SS^S&ii W25 S&S 



United States (naturalised in New Zealand and Australia, also 

 in Ireland). SYNS. S. aneeps, S. yramineum (B. M. 464). 



SisyrincMum continued. 

 S. Bermndlana (Bennndan). This differs from S. an<nift\foKw 



in being much larger in all its parts, and strikingly so in its 



broad leaves, which are equitant at the base. k. lift, to 2ft. 



Bermudas. SYX. & iridioides (B. M. 94). 



S. californicum (Californian). ./f. many in succession, scentless ; 

 planate, the segments obovate- 



perianth of a uniform yellow, 



oblong, obtuse; anthers orange-coloured; fascicle many-flowered; 

 scape quite simple, longer than the leaves, curved. Autumn. 

 1. several, distichous, 1ft. to nearly 2ft. high, about $in. broad, 

 linear-ensiform. California, 1796. Half-hardy. SYX. Mariea 

 caltfornica (B. M. 983). 



S. chilense (Chilian), fl., perianth i purple, yellow at the base, 

 long ; bracts leaf-like ; spathe linear, acuminate. 



three to five lines lon^. . 



about three-flowered; peduncles 



lexuous, very slender, lin. to 



Uin. long. July. L, radical ones linear-ensiform, striated, Sin. 

 to 12in. long, one to two lines broad. Stem 6in. to 12in. high, 

 flexuous. Brazil, Ac., 1826. Half-hardy. (B. M. 2786.) 



5. DouglasU (Douglas'). A synonym of S. grandiflorum. 



6. filifolinm (thread-leaved).* fl. campanulate, erect ; perianth 

 whit*, like porcelain, each segment delicately lined with pale 

 purplish-red. May. h. 6in. to Sin. Falkland Islands, 1885. 

 Plant of Rush-like habit (B M. 6829 ; G. C. n. s., xxiii. p. 696.) 



S. graminenm (grass-like). A synonym of S. angtutifolivm. 

 S. graminlfolium (grass-leaved), fl. slightly exserted above the 



spathe; perianth yellow, the segments obovate, mucronate; 



spathes terminal, few or many-flowered, the outer one leafy, liin. 



long, the inner lin. long. ApriL I., radical ones Sin. long, 



scabrous on the margins, acuminate, sheathing at base ; cauline 



ones Sin. to 6in. long. Stem branched, erect, 7in. to 9in. high. 



Chili, 1825. Half-hardy. (B. R. 1067.) 

 S. g. ascendens (ascending), fl., spathes very hairy, equal 



L, radical ones 4in. to 6in. long; cauline ones 2in. to Sin. long, 



alternate. Stem Sin. to 9m. high. (B. R. 1914, under name of 



S. g. pumilum.) 

 S. g. maculatrun (spotted), a., perianth segments marked with 



dark blood-coloured spots. (B. M. 3197, under name of 5. maeu- 



PIG. 490. SISYRIXCHIUK GRANDIFLORDM. 





