1656 



SEMPERVIVUM 



ren rosettes 1-1 K in. across, the new ones on stalks 1-2 

 in long- Ivs pale green and pubescent all over, only 

 thevery'tip red-brown: fls. U4-l% in. across, yellow. 

 Eastern Eu., Asia Minor. B.M. 507 and 2115 (as S. glo- 

 biferu>n).-The showiest of all the hardy species. 



11 Heiiffelii, Schott. Height 6-8 in. : barren rosettes 

 IK-gin across, not peduncled: Ivs. 30-40 in a rosette, 

 obovate - cuneate, the upper third or even half tinted 

 bright red-brown : panicle dense, many-fld., 2/6-3 in. 

 across Us an inch or less across, pale straw-yellow; 

 netals with 3 small cusps, not flmbriate. Aug. Mts. of 

 Transylvania and Greece, 5,000-6,000 ft. -One of the 

 latest in flower. 



12. globiferum, Linn. (S. soboliferum, Sims). HEN- 

 AND-CHICKENS. HousELEEK. Height 6-9 in.: barren 

 rosettes globose, 1-1% in. thick, the numerous young 

 ones attached to the parent only by a slender thread 

 and easily becoming detached from it and rolling about: 

 Ivs. 60-80 in a rosette, obovate-cuneate, the outer ones 

 tipped red -brown, especially on the back: fls. 1 in. 

 across, pale yellow; petals obscurely tricuspidate, con- 

 spicuously flmbriated at the edge and on the prominent 

 keel. Mts. of Austria. B.M. 1457,-Unless the young 

 rosettes are thinned out the plants are not so likely to 

 flower. Under the name of S. globiferum, Linnaeus 

 seems to have confused all the yellow-fid, hardy species 

 which he knew. 



13. arenarium, Koch. Very close to S. globiferum, 

 having the same height, the same globular deciduous 

 rosette, etc., but with narrower Ivs. and the petals 

 larger and more strongly flmbriated: Ivs. oblanceolate : 

 fls. 1-1% in. across; petals pale yellow, distinctly tri- 

 cuspidate, with a linear end tooth, strongly fimbriated 

 at the edge and less so on the prominent keel. Tyrol. 

 Gn. 49, p. 220. 



R. rupestris is advertised by one American dealer, but it 

 seems to be unknown to botanists. W. M. 



SENEBIERA (after Joh. Senebier, a naturalist of 

 Geneva). Cruciferce. About 6 species of procumbent 

 annual or biennial herbs from the temperate regions of 

 Europe and Asia, and Australia, with alternate, entire 

 or pinnately cut Ivs. and small white or rarely purple 

 fls., in short, axillary racemes: sepals short, spread- 

 ing, equal at the base; stamens free; siliques in pairs, 

 small, laterally compressed; valves 1-seeded, indehis- 

 cent. 



pinnatifida, DO. A common weed in many parts of 

 the world and sometimes used as a pot-herb in foreign 

 countries: plant %-l ft. high: Ivs. pinnately lobed: 

 fls. white, small, numerous j\ 'vy, BARCLAY. 



SENECA SNAKEROOT. Polygala Senega. 



SENECIO (Latin name for plants of this genus, ulti- 

 mately from senex, "old man"; said to be in allusion 

 to the hoary pappus). Compdsitce. GROUNDSEL. The 

 largest genus of plants, comprising some 1,200 species 

 in all parts of the world. A genus comprising so many 

 members and being so widely distributed is necessarily 

 variable and therefore practically impossible of defini- 

 tion. A distinguishing mark of the Senecios lies in the 

 character of the involucre, scales in one series, and 

 usually reinforced at the base by a row of shorter scales 

 that give the head the appearance of having a small 

 calyx. The heads are usually radiate, the ray-florets 

 being pistillate and fertile; but sometimes the pays are 

 absent and then the head is homogamous^.(5oTets all of 

 one kind, i. e., perfect). The dis^ftefets are tubular 

 and 5-toothed. The torus or receptacle is usually naked. 

 The akenes are mostly terete and ribbed; pappus of 

 soft whitish, often copious bristles. According to Gray, 

 "minute short hairs or papillae on the akenes of most 

 species swell and emit a pair of spiral threads when 

 wetted. Before wetting, the akenes may be really or 

 apparently glabrous, and after wetting become canes- 

 cent." Most of the Senecios are yellow-rayed. Of the 

 vast number of species, very few have gained promi- 

 nence as cultivated subjects. If we omit the greenhouse 

 Cineraria (which is technically a Senecio as understood 

 by Bentham & Hooker), the most popular species are 



SENECIO 



the Farfugium grande (properly Senecio Kcempferi) of 

 florists, S. mikanioides or German ivy, S. elegans or 

 purple ragwort, and S. Cineraria, one of the plants 

 commonly known as dusty miller. Various other plants 

 are known as dusty miller, and one of them (Fig. 2312) 

 is sometimes confounded with Senecio Cineraria. 



All other species are of very minor importance to the 

 horticulturist. Of the 60 or more species native to the 



2312. Artemisia Stelleriana, one of the Dusty Millers some- 

 times confused with Senecio Cineraria. See Fig. 2315. 



United States and Canada, about a half dozen have been 

 offered by dealers in native plants, but they are practi- 

 cally unknown horticulturally. Most of the species are 

 wholly herbaceous, but in South Africa and South 

 America many species are shrubby. Some species are 

 even arborescent; others are climbers. In South Africa 

 and the Canaries is a set that has been separated as 

 Kleinia, distinguished mostly by its habit, being for 

 the most part fleshy shrubs or herbs, with terete or an- 

 gular stems and whitish or pale yellow rayless flowers. 

 Species of this group are sometimes seen in collections 

 of succulents, but they are little known outside of 

 botanic gardens. S. vulgaris, Linn., from Europe, is a 

 common annual' weed in various parts of this country. 

 To Senecio belong the genera known to gardeners as 

 Erythrochaete, Farfugium, Jacobaea, Kleinia, Ligularia. 

 Cineraria is also a Senecio, but the florist's Cineraria 

 is described under that name in Vol. I of this work. 

 Bentham & Hooker refer to Senecio the genus Cacalia, 

 which is kept distinct by American botanists. Hoff- 

 mann (in Engler & Prantl's Natilrlichen Pflanzenfa- 

 milien) refers the garden genus Emilia to Senecio, but 

 keeps Ligularia (including Farfugium) and Cineraria 

 distinct. For S. conchifolius, see Emilia. 



Since Senecios afford both greenhouse and hardy 

 border plants, it is impossible to give general cultural 

 directions. The species are not difficult to manage, 

 however, and most of them propagate readily by means 

 of greenwood cuttings and seeds; the hardy species 

 may be divided. 



