898 LEGUMES 



It has been shown, first in 18SG by experiments con- 

 ducted by Hellriegel and Wilfarth and later by numer- 

 ous other investigators, that when Legumes are grown 

 in sterilized sand, which contains no trace of nitrogen, 

 they soon die of nitrogen-hunger, and no tubercles are 

 formed on thfiir ni.its. If. hoWL-vur. a very small quan- 

 tity of soil extr:pM .ir "I i.:i iri ii<l . 1,'rown from root- 

 tubercles, is :iiM ! '.. I ;,. - r .', i : . ts as- 

 sume new vii; 't ■■•• •' < ■ i- n i ,; ;■ > . Tu- 

 bercles are fi.nu. I "n lli- hhI-. r.ud tlie 

 plants are found t.> contuin more nitrogen 

 than was present in the seed. By such ex- 

 periments it is shown that Legumes can ac- 

 quire free nitrogen through the agency of the 

 bacteroids. The physiological process by 

 which this is done is still obscure. 



Some species of Legumes can be innocu- 

 lated by bacteroids from other species, but 

 others seem to be dependent upon their own 

 specific organism. The organisms are spread 

 in the soil only by mechanical agencies, such 

 as working the soil, moving water, wind, etc. 

 If the soil is rich in nitrogen, leguminous 

 plants can develop, like all others, without 

 the aid of tubercles. 



Recently pure cultures of bacteroids have 

 been oflfered in the market as Nitragin, to be 

 used for the pnrpn<;c of innnciilntiiiL' soils de- 

 ficient in micro. .i-aniMi.-;. Altlion-li several 

 experimenters flann suricv^ wiili this sub- 

 stance, its pnirtiral :l|.|.I [.Ml i,.ii to a-rii'ulture 

 remains yet to bL- ilLuiuustrutLd. The sub- 

 stance sold as Aliuit, and said to enable 

 grasses to acquire free nitrogen, is merely a 

 pure culture of a very common bacterium 

 present in all decaying matter. 



Heinkich Hasselbring. 



LEIOPH'tLLUM (from leios, smooth and 

 phyllon : referring to the smooth foliage). 

 Syn., />■ iKlrhdii . Ammyrsine. EricAcect. 

 Sanii M\lti,i'. Kvcrgreen hardy densely 

 braiirit, <l ^linili, sometimes procumbent, 

 with Mniill. ,uH;ii»rous, opposite or alternate 

 crowded Ivs. aiid white or light pink small 

 fls. in terminal raany-fld. umbels, appearing 

 profusely late in spring. It resembles in ap- 

 pearance somewhat the Dwarf Box, and is 

 well adapted for borders of evergreen shrub- 

 beries and also for rockeries. It thrives best 

 in a peaty or very sandy, loamy soil and as 

 well in a sunny as in a partly shaded posi- 

 tion. Prop, by seeds sown in pans and placed 

 in a cool frame or by layers put down in fall. 

 One species in E. N. Amer. from N. J. to 

 Fla. Allied to Ledum. Lvs. entire: fls. in 

 terminal, umbelliform corymbs ; sepals and 

 petals 5; stamens 10: fr. a 2-5-celled dehis- 

 cent many-seeded capsule. 



buxifdlium. Ell. (Liditm buxifdIium,'BeTg.). 

 Dense, leafy bush, to 3 ft. high: Ivs. short- 

 petioled, thick, oval or obovate, about K in. 

 long; fls. white, pinkish outside, about one- 

 fifth in. across, on slender pedicels; petals 

 elliptic, almost twice as long as sepals. April- 

 June. Pine barrens and mountains, N. J. to 

 Fla. B.M. (i752. Gn. 42. p. 559. G.W.F.A. 

 49. B.R. 7:531 (as Ammyrsine). L.B.C. 1:52 

 (as Ledum). Var. prostritum, Gray. Form- 

 ing dense depressed tufts: lvs. usually oval, 

 and deep green. High mountains of Carolina. 

 Alfred Rehdee. 



LfiMNA (Greek, limite ; a large pool of 

 standing water). LemnAcem. Duckweed. 

 DucKSMEAT. Duckweeds are common upon stagnant 

 pools, often covering the water with a blanket of green. 

 They are easily gathered for schoolroom and home 

 aquaria, and may be procured from specialists in aqua- 

 tics and native plants. Ducks and carp eat these plants 

 greedilj;. One of the common Duckweeds is shown 6 

 times its natural size in Fig. 1259. Duckweeds are small 

 floating plants, without any distinct stems, a whole 



LEMON 



plant commonly consisting of one leaf and one un- 

 branched root which has no vascular tissue. These lvs. 

 are called fronds by the botanist largely because lvs. 

 do not ordinarily emit roots. The plants grow separ- 

 ately, or cohere by their edges in 2's or 3's, and multi- 

 ply by similar fronds, which grow out of the edges of 

 the old ones something like buds. The flowers are 

 minute and appear on the edge of the 

 frond. They consist of a pistil and generally 

 2 stamens which are inclosed in a sheath, 

 which the botanists have determined is a 

 spathe by reason of the place where it is 

 borne and by homology with related plants. 

 L. minor is said to flower more frequently 

 than any other northern species. Details of its 

 flower are shown in Fig. 1260,where there seem 

 to be 4 anthers, but there are only 2, each 

 bearing 2 locules. Some botanists consider 

 the 2 stamens as 2 Hs. and the ).iiitil a third 

 flower. Duckweeds are pcinnnal plants. In 



the 



the 



fall 



ditch or pond, but rise ai/aio in tlo^ ~i'riiig. 



contains the smallest (loiv i : m the 



vegetable kingdom. Tier. !1 <\n-- 



cies of Duckweeds, widel;, ■ ; o / /"./,(/- 

 rliiza is commonly knowi) in Are 1 1. in i>oiaii- 

 ies as Splrodela pohjrliUn. but .'>|piiudela is 

 considered by Bentham and Hooker a sub- 

 genus of Lemna. The common Duckweed 

 occasionally infests the small lily ponds (arti- 

 ficial ones), where it is a pest. The simple 

 remedy is to flush the pond and see that com- 

 mon goldfish or carp are in sufiicient numbers 

 to clear off the remainder. 



A. Veins 7-11: roots several. 



polyrhlza, Linn. {SpirodHa polyrhlza, 



Schleid.). Also spelled polyrrhiza. Fronds 



broadly ovate or orbicular, attaining 3 or 4 



lines d'iam. B.B. 1:365. 



AA. Veins 1-5 : root solitary. 

 B. fronds oblong, 6 lines long, 3 lines wide, 

 trisiilca, Linn. Fronds much thinner than 

 in the next, narrow and minutely toothed at 

 one end, thicker and taslk-like at the other, 

 usually with 2 young ones growing from op- 

 posite sides near the base. B.B. 1:300. V. 

 3:200. 



EB. Fronds broadly ovate or orbicular, 



t lines long. 

 minor, Linn. Figs. 1259-00. Fronds usu- 

 ally cohering in 3's or 4s. rather thick, not 

 minutely toothed. B.B. 1:366. V. 3:200. 

 Wm. Tricker and W. M. 



LEMON culture in Florida was assuming 

 an important share of horticultural work 

 previous to the cold winter of 1894-5, but 

 siiH-e then attention has been more largely 

 i/iven to hai.lierfruits. The growing of Lemon 

 tries is Ihi; inning again in lower Florida, 

 in seitii.li- tree from killing frosts, and al- 

 tle.nuh soil loiiditions are rather unfavorable 

 t« the cultivation of citrous trees, owing to 

 the jrocVy or poor character of the ground, 

 there is evidence of interest and some practi- 

 cal results from the experimental plantations. 

 There remained after the killing freezes some 

 younK plant isolated orchards of Lemons in southern 

 of garden pea. Florida, which have since entirely recovered 



Natural size. and have borne full crops of fruit for two or 



three years. 

 The pecuniary reward to a careful Lemon grower is 

 large, provided he has suitable soil and a situation re- 

 moved from killing frosts, and, although profits from 

 other citrous fruits nuvv be temporarily larger. Lemons 

 are constarii l\ in .l.-ni ni.l, ;in.| I he reward Is Correspond- 

 ingly eeii .; 11 , ., iially set with budded 

 trees, all.. I ' i .i . .| ., The young trees after 

 setting are ai|v,'int;m<"in-ly ninhlied with grass or other 



1258. Nodules < 



