1444 



HELIAMPHORA 



HELI ANTHEM UM 



who brought plants to England. It is a rhizomatous 

 plant, and is prop, by single crowns. The plant is 

 described as growing weU in small pots in a mixture of 

 peat, sphagnum and sand, surfaced with sphagnum, 

 the pot plunged to the rim in moss and kept under a 

 bell-glass. It requires much moisture. l_ jj_ B. 



HELIANTHELLA (the plant resembles Helianthus). 

 Composila'. Hardy perennial herbs from North 

 America, with showy yellow heads borne in autumn. 



Stem commonly unbranched: Ivs. mostly scattered 

 and sessile, hnear or lanceolate, entire: heads solitary 

 or few, with yellow infertile rays and a yellow or brown- 

 ish disk. — Thirteen species. Helianthella belongs to a 

 group of genera distinguished from Helianthus by 

 having the frs. laterally comjiressed instead of thick 

 and obtusely angled. Other cult, genera of this group 

 are Actinomeris, Encelia and Verbesina, which are dis- 

 tinguished from one another by combinations of fr. 

 and pappus characters. 



The single species in cultivation is easily grown in a 

 variety of soils, and is propagated by seeds or by 

 dividing the rootstocks. 



quinquenervis, Gray. St. 2-4 ft. high, nearly 

 smooth: Ivs. mostly opposite, 4-9 in. long, the upper 

 sessile: heads 3-5 in. broad, long-stalked, solitary or a 

 few below in the axils of the Ivs., with an involucre of 

 large, leafy bracts; rays 15-20, pale yellow, 13^^ in. 

 long. June-Sept. Rocky Mts. g. w. Fletcher. 



HELIANTHEMUM {Greek for sm floicer). Includ- 

 ing Hdrmiiuiii, Titberaria and Fumana. Cistqcese. Sun 

 Rose. Ornamental woody or herbaceous plants grown 

 chiefly for their showy flowers. 



Half -evergreen or evergreen low, 

 upright or prostrate shrubs or 

 perennial herbs, rarely annual: Ivs. 

 usually opposite, or the upper ones 

 alternate, rarely 

 all alternate, 

 small, entire, 

 with or without 

 stipules : fls. in 

 terminal race- 

 mose, umbellate 

 or subcapitate cymes, 

 rarely sohtary, mostly 

 yellow, sometimes of 

 2 kinds, earlier fls. 

 with large petals and 

 later fls. with small 

 or without petals; 

 sepals 3, or 5 and 

 unequal; petals 5; 

 stamens many ; ovary 

 1 - celled or imper- 

 fectly 3-ceUed, with 

 slender or short style; 

 caps. 3-valved with 

 many or several 

 seeds ; embryo curved 

 hke a ring or hook (subgen. Halimium), or straight 

 or folded (Helianthemum proper). — About 110 species 

 in N. Amer. (and 3 in. S. Amer.), Eu., N. Afr. and W. 

 Asia. Monograph by Grosser in Engler, Das Pflan- 

 zenreich, lift. 14. Cistaceae, pp. 33-131 (11303) ; another 

 important work is Sweet's Cistinea (1825-30) where 

 many species are figured, quoted below as S. C. 



The helianthemums are mostly suffruticose or 

 shrubby, less often herbaceous plants, either upright 

 and low, or ccspitose or prostrate, with small and 

 usually narrow, often grayish fohage and with yellow 

 or white, less often pink or red, usually profusely pro- 

 duced flowers in terminal racemes or clusters, rarely 

 solitary, appearing din'ing the summer and followed by 

 a capsular fruit inclosed or surrounded by the persistent 



1793. Helianthemum Chamsecistus. 



(XJi) 



sepals; the flowers open only in the sun and the delicate 

 petals soon drop. Most of the species are not hardy 

 North without protection and are particularly suited 

 to warmer and drier climates, but H. Chamsecistus is 

 fairly hardy North, though in exposed situations it 

 also profits by a protection of mulch: the hardiest of 

 the species mentioned below is H. canadense, but it is 

 at the same time the least attractive. They all thrive 

 well in poor sandy or rocky soil, most of them being 

 partial to limestone soil, and demand a sunny position 

 to bloom profusely. They are especially adapted for 

 rockeries and borders particularly the numerous forms 

 of H. Cham^cislus which form dense mats; most of the 

 other species are of low twiggy habit. Propagation 

 is mostly by division, also by greenwood cuttings and 

 by seeds which germinate readily, but if several species 

 are grown together the seeds are hable to produce 

 hybrids. 



INDEX. 



algarvense, 2. 

 angustifolium, 7. 

 appeninuni, 6. 

 canadense, 1. 

 Chamsecistus, 7. 

 cupreum, 7, 8. 

 diversifoUum, 7. 

 formosum, 3. 

 grancUflorum, 7. 



hyssopifolium, 7. 

 lasianthum, 3. 

 macranthum, 7. 

 mulliplex, 7. 

 mutabile, 7. 

 ocymoides, 2. 

 pilosuni, 5. 

 polifolium, 6, 7. 

 pulverulentum, 6. 



rhodanthum, 6. 

 roseum, 6, 7, 8. 

 stramineum, 7. 

 sulphureum, 8. 

 tomentosum, 7. 

 umbellatum, 4. 

 variahile, 7. 

 venustum, 7. 

 vulgare, 7. 



A. Style short and straight, or almost wanting: Ivs. with- 



out stipules. (Halimium.') 



B. Fls. of 2 kinds, the larger solitary or rarely in 2's, the 



smaller apetaloiis ones clustered on lateral branch- 

 lets; sepals ,5. 



1. canadense, Michx. (Halimium canadense, Grosser). 

 Frostweed. Upright, 1-2 ft., hoary pubescent: Ivs. 

 nearly sessile, oblong to linear-lanceolate, acutish, pale 

 beneath, }^-l}^ in. long: the larger fls. 1 in. across, yel- 

 low; sepals 5, the outer linear, the inner ovate, tomen- 

 tulose. Junj^Aug. Maine to Mich., south to N. C. and 

 Miss. — Occasionally offered by dealers in native plants. 



BB. Fls. all large and showy, 1^2-2 in. across; sepals 3. 



c. Color of fls. yellow. 



2. ocymoides, Pers. (H. algarvcnse. Dun. Cistus 

 algarvensis, Sims). Nearly erect, twiggy shrub, 2-3 

 ft., hoary-pubescent: Ivs. short-petioled, oblong-lanceo- 

 late to oblong-spatulate, recurved at the apex, grayish, 

 those of the flowering branchlets sessile, green, Hrl^, 

 rarely to 1}^ in. long: fls. yellow with purple eye, 13^ 

 in. across, in loose, long-stalked corymbose clusters; 

 sepals ovate-lanceolate. Spain and Portugal. B.M. 

 627, 5621. S.C. 40, and vars. 26, 65, 96. 



3. lasianthum, Pers. (H. formosum, Dun. Cistus 

 formbsus, Curtis). Spreading upright shrub, tomen- 

 tose: Ivs. short-stalked, oval to ovate-oblong or lanceo- 

 late, obtuse or acutish, often revolute on the margin, 

 white-tomentose while young, |^-1 in. long: fls. yellow, 

 the petals often spotted purple at the base, 2 in. across, 

 in 1-5-fld. cynies; sepals ovate. Spain and Portugal. 

 B.M. 264. S.C. 50. Gn. 26:420; 53, p. 131. G.M. 

 34:246. F.S.R. 2, p. 45. G. 16:382.— The most showy 

 species of the genus. 



cc. Color of fls. white. 



4. umbellatum, Mill. (Cistus umbellatus, Linn.). 

 Low shrub, upright or procumbent, 1-2 ft. : Ivs. sessile, 

 hnear or hnear-lanceolate, grayish tomentose beneath, 

 pubescent above, later glabrescent, more or less viscid, 

 %-l]4,in. long: fls. about 1 in. across, in whorls or race- 

 mose whorls; sepals ovate. Cent. S. Eu. N. Afr. S.C. 5. 



AA. Styles slender, often curved; sepals 5, the 2 outer ones 

 smaller. (Helianthemum proper.) 



B. Stipules subulate, the lower and middle ones about as 

 long as petioles: fls. while or pink. 



5. pilfisum, Pers. Low nearly upright or ascending 

 subshrub: Ivs. short-petioled, hnear or oblong, revolute. 



