I achenes surrounded by a wing which is 

 I notched at the summit, and usually (but 

 I not always) terminates in two short awn- 

 ! like teeth, which represent the pappus. 

 | The most interesting species is the Com- 

 pass-plant, 5. laciniatum, of which Dr. Asa 

 ; Gray writes :—' On the wide open prairies j 

 ' the leaves are said to present their faces 

 uniformly north and south, whence it is 

 called the Compass-plant.' In a paper re- 

 > lating to this plant, communicated to the 

 Botanical Society of Edinburgh in January 

 I 1862 by Mr. Gorrie, there are various notices i 

 of the plant by different travellers; but j 

 Mr. Gorrie states that he is unable to de- j 

 termine the correctness of their observa- j 

 tions, and until a competent botanist shall 

 assert that the ' broad flap leaves of this 

 I plant point due north and south with an 

 | accuracy as unvarying as that of the mag- 

 ■ netic needle,' we shall be slow to believe 

 ! that such is the case— the more so when we 

 j find such a note as the following of Lieut. 

 : J.W.Albert of the United States Army: 'It j 

 : is said that the planes of the leaves of this 

 : plant (,S. laciniatum) are coincident with ; 

 [ the planes of the meridian, but those I 

 have noticed must have been influenced 

 by some local attraction that deranged 

 j their polarity.' The plant is also known as 

 Pilot-weed, Polar-plant, Rosin-weed, and 

 | Turpentine-weed— the latter names from j 

 I the abundant resin exuded by its stems, i 

 which grow to a height of three to six feet, j 

 as well as by the leaves, which are ovate I 

 in outline, and deeply pinnatifid, the seg- 

 ments being again divided. The tuberous i 

 roots of S. lave, a plant with smooth 

 dock-like leaves, are eaten by the natives 

 of the Columbia River valley. 8. terebin- 

 thaceum is sometimes called the Prairie 

 Burdock, from its rough heart-shaped root- 

 leaves, about two feet in length, resembling 

 those of the burdock ; and »S'. perfoliatum 

 gets the name of Cup-plant, because the 

 winged stalks of its opposite leaves are 

 united together so as to form a cup with 

 the stem in its centre. These two last, with 

 the Compass-plant and others, have been 

 cultivated in English gardens. [A. A. B.] 



SILPHIUM. A gum-resin supposed by 

 some to be obtained frnm Thapsia SUphion, 

 and by others from Prangos pabularia. 



SILVER-BUSH. Anthyllis Barba-jovis. | 



SILVER-GRAIN. The glittering plates ' 

 observed in the wood of many exogens, 

 and caused by the division of the medul- 

 lary plates. 



SILVER-TREE. Leucadendron argen- 



SILVER-WEED. Polentilla. anserina; 

 also Argyreia. 



SILVER-WOOD. Mouriria ; also Guet- 

 tarda argentea and Quelania tetioid.es. 



SILVERY. Having a whitish metallic 

 lustre. 



SILVIA. A genus of SerophulariacecE, 

 containing two small prostrate under 



shrubs from Mexico, with opposite leaves, 

 and large yellow flowers. The calyx is tu- 

 bular-campanulate, with the apex divided 

 into five imbricate lobes; the tube of the 

 corolla is long, and the spreading limb is 

 deeply cut ; the stamens are included, and 

 the parallel cells of the anthers are nearly 

 equal, and slightly mucronateat their base; 

 the capsule is ovate and acute. [W. C] 



SILVBUM. Robust herbaceous plants 

 belonging to the thistle group of Compo- 

 site, amomg which they are distinguished 

 by having the filaments united, and the 

 pappus in many rows. S. Marianum, the 

 Milk Thistle, grows to the height of three 

 to four feet or more, with a furrowed stem, 

 and large spreading wavy spinous leaves, of 

 which those next the root are pinnatifid, 

 and variegated with green and milk-white. 

 The involucre is subglobose and spinous, 

 and the florets purple with long tubes. 

 The specific name Marianum was given to 

 this plant to preserve the legend that the 

 white stain on the leaves was caused by 

 the falling of a drop of the Virgin Mary's 

 milk. It was formerly cultivated, the 

 young leaves being used as a spring salad, 

 the root boiled as a potherb, and the heads 

 treated like the heads of the artichoke. It 

 grows wild in waste places in many parts 

 of England, and still retains its place in 

 old-fashioned gardens. French : C liar don 

 Marie; Carthame macule. [C. A. J.] 



SIMABA. A genus of Simarubaceoe, con- 

 sisting of trees and shrubs, natives of Tro- 

 pical America, having the leaves alternate, 

 and either simple or ternate or pinnate, 

 and the flowers in axillary masses or ra- 

 cemes. The calyx is small; the petals 

 four or five, long and spreading ; and the 

 stamens eight or ten, each filament having 

 a scale adherent to it. The ovary consists 

 of four or five carpels, the styles of which 

 are distinct, but become united above into 

 one having a five-lobed stigma. The fruit 

 is a drupe but often dry, usually having 

 the same number of carpels as the ovary. 



Among the species S. Cedron is very re- 

 markable for the properties of its seed. It 

 is distinguished by its large pinnated 

 leaves with twenty or more narrow ellip- 

 tical leaflets, and its large panicles of flow- 

 ers, which are three or four feet long. It 

 is a small tree, native of New Grenada, 

 and bears a fruit about the size of a swan's' 

 egg, containing only one seed, four of the 

 cells being barren. 



The Celron of commerce, which looks 

 like a blanched almond but is larger, is 

 the kernel of the fruit. As a remedy for 

 the bites of serpents it appears to have 

 been known to the inhabitants from time 

 immemorial, and was first reported in this 

 country as deserving of notice in 1699, but 

 it was not till very recently that anything 

 certain was known either of the seed or its 

 uses. Part of its reputation is owing to its 

 febrifugal powers in intermittent fever, 

 it being successfully prescribed in that 

 disease by the physicians of New Grenada, 

 a country abounding in forests of quina- 

 trees ; but it principally rests upon its 



