18o8 



LIGHT 



LIGULARIA 



In tlif tvnst nirl ion of (tn>onhouscs, therefore, it is 

 imjxirtant they slunild Ix^ (iosipmnl to imiduce the 

 m:i.\iniuni n\sults during the critical lij;lit seasons. 

 Thctirelical diajtranis an- shown in Figs. L'l 11 S. 



Fi\>ni a stiuly of the liglit conditions in greenhouses, 

 it has Invn found tliat large ghiss is sujierior to small 

 glass Infiutse of the smaller amount of light-obstructing 



2148. Showing type of greenhouse constructed to obtain the maximum 

 amount of light in short winter days. Modification of type shown in Fig. 

 2147. Obstructs more light than Fig. 2147, but could be built wider. 



framework, but with present methods <>i construction 

 there is a limit to the size of ghtss tliat can be .safely 

 employed. Moreover, high-angled roofs are much 

 suixrior to low roofs from the light point of view, but 

 their practical utility is somewhat limited. Experi- 

 ments with ditTerent t^^>cs of gl;i.ss have shown that 

 there may exist 18 |X'r cent difference in the light-trans- 

 mitting proyx-rties of No. 1 and No. 2 quality gla.ss, 

 and third quality ghuss is 33 per cent less effective 

 than No. 1 Duality. A .slight annual dc^terioration in 

 grccnhou.sc glass must be expected owing to the for- 

 mation of a film of oil, but this can be obviated to some 

 e.vtent. The nature of the reflecting surface of the 

 greenhouse, degree of lapping, and other factors influ- 

 ence light. In the modern large house more uniform 

 light conditions are obtained than in the early, .smaller 

 houses. 



As regards the direction of tlie greenhouse, for most 

 pur]>os<'S the east and west house is ))referable for 

 obtaining light, but .some crops are able to thrive better, 

 especially in the spring months, in a hou.se running 

 north and south. Morning light being superior to 

 afternoon light, an east and west house should bo 

 tiltwl somewhat toward tlie northea-st, thus exposing 

 the plants more directly to the morning light and mak- 

 ing It pos-sible to .syringe with less liability to fungous 

 infection of the plants. 



LUeralure. 



L. Jost, "Vorlesungen uber Pflanzenijlivsiologie," 

 3d edition, HH3; .1. Wie.sner, "Der Liditgenu.ss der 

 Pflanwn," 1907; (i. E. Stone, "The Relation of Light 

 to Grwnhou.sf; Culture," Mass. Agr. Exp. Station Hull. 

 No. 144, 1913; E. O. Pringsheim, "Reizbew(^gungen der 

 Pflanwn," 1912; C. Darwin, "Tlie Power of .Movement 

 in Plant*," 18H0; VV. Uothert, "Cohns Heitr. /,. Biol. d. 

 Pfianzf:n," M. 7. lS(i6; A. 11. Hlaauw, "Extr. d. rec. 

 des travaux bot. m'rerl. .5, 19<Ht;" II. Fitting, "Jahrb. s. 

 wijw. Ik)t. Band. 38. 41.44"; D.T. MacDougal, Memoirs 

 New York Botanical Garden, ^'Mi. q £ Stone. 



LIGHTFOOTIA fRev. John Lightfoot, 1735-1788, 

 author of a flora of Swjtland). ('(imyanuUiceiP. Under- 

 shnitiS or herlw ^annual, biennial, perennial), of Afr. 

 and Ma'lagai^car, with very small blue, white or pink 

 fifl.: Ivg. n.-njally alt/^mate CHornetimes fstscicled or oppo- 

 site), f;ntire or toothed, small, narrow and rigid: fls. 

 varioafly arrangwl; calyx-tube adnata to ovary, the 



lobes persistent; corolla deeply .Wobed or partial nearly 

 to ba.se, the stamens free: fr. a ca])s. dehiscing at the 

 top. Species 4D-.'")t), Trop. Afr. to the Cape region. 

 Two or three species are more or less mentioned in 

 garilen writings for greenhou.se culture, hut apparently 

 none is in tlie trade. L. Uin'lld, Ijodd. (L. ciliala, 

 Sond.), of the Cape, hjus erect woody branches and 

 bluish racemo.se fls. : Ivs. ovate-lanceolate, some- 

 what reflexed: 9 in. L.H.C. 1 1 : 103S. L. siihulatn, 

 L'ller. (L.ticitiili flora, Sond.). Lvs. very narrow, 

 more or less spreading: st. a.scentling or erect, 

 somewhat woody: fls. many, blue: 12-18 in. 

 ('ape- " L. H. B. 



LIGULARIA (name refers to the strap-sliaped 

 iiioi-e or. less bilabiate rays). Including Fnr- 

 fiiijiiini antl EnjlhrochMi'. ConipuniU-. Perennial 

 herbs, some growii in tlie open for the striking 

 flower-heads and leaves, but mostly indoors for 

 the large and interesting fohage, or in summer 

 bedding. 



From Senecio, to which it is often referred, 

 this genus differs largely in the character of the 

 involucre, the scales or bracts of which are in 

 one series at the insertion but of two forms so 

 that the narrow outer ones overlap the edges 

 of the broader inner ones; also in technical 

 characters of the style. Lvs. mostly long- 

 pet ioled, broad or even orbicular or reniform, some- 

 times palmate, those on the st. smaller and bearing 

 large sheaths: heads large, reflexed or nodding, in 

 corymbs or racemes; ligules or rays mostly long and 

 narrow, usually yellow: achcne glabrous, bearing soft 

 pappus. — Species about 30, as now defined, from W. 

 Eu. to Siberia, Himalayas and China-Japan. The 

 plants impose no sjiecial difficulties in cult. They are 

 Ijrop. mostly by division. 



Kaempferi, Sieb. & Zucc. (L. Farfugiuni, C. Koch. 

 FdrfUijiuiii Kacmpjcri, Henth. Senecio Kaempferi, DC). 

 Rhizomatous perennial sending up many lvs. on slen- 

 der flocculent- woolly ]ietioles: lvs. large (often 6-10 

 in. across), orbicular to nearly reniform, cordate at 

 base, angular-toothed, green: fi.-,sts. 1-2 ft. tall, floc- 

 culent-woolly, branche<l, with only small, bract^like 

 lvs.: heads large, with light yellow rays spreading 

 lJ^-2 in. across; pappus white and copious. Japan. 

 Var. aftreo-maculatus, Hort. (Farfugiuni grdnde, 



2140. 



Leopard plant, or Farfugium — ^Ligularia Kaempferi 

 var. aureo-maculatus. ( X %) 



