898 



LEGUMES 



LEMON 



It has been shown, first in 1886 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 their roots. If, however, a very small quan- 

 tity of soil extract or of bacteroids, grown from root- 

 tubercles, is added to the sand, the plants as- 

 sume new vigor and grow to maturity. Tu- 

 bercles are formed on the roots, and the 

 plants are found to contain 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 offered in the market as Nitragin, to be 

 used for the purpose of innoculating soils de- 

 ficient in micro-organisms. Although several 

 experimenters claim success with this sub- 

 stance, its practical application to agriculture 

 remains yet to be demonstrated. The sub- 

 stance sold as Alinit, and said to enable 

 grasses to acquire free nitrogen, is merely a 

 pure culture of a very common bacterium 

 present in all decaying matter. 



HEINRICH HASSELBRING. 



LEIOPH?LLUM (from leios, smooth and 

 phyllon ; referring to the smooth foliage). 

 Syn., Dendrium, Ammyrsine. Ericacece. 

 SAND MYRTLE. Evergreen hardy densely 

 branched shrub, sometimes procumbent, 

 with small, glabrous, opposite or alternate 

 crowded Ivs. and white or light pink small 

 fls. in terminal many-fid, 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. (Ledum buxifdlium,T$erg.). 

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

 petioled, thick, oval or obovate, about % 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. 6752. Gn. 42, p. 559. G.W.F.A. 

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

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

 ing dense depressed tufts: Ivs. usually oval, 

 and deep green. High mountains of Carolina. 

 ALFRED REHDER. 



LMNA (Greek, limne ; a large pool of 

 standing water). Z/emnacece. 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 

 greedily. 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 



1258. Nodules on the 



roots of a young plant 



of garden pea. 



Natural size. 



plant commonly consisting of one leaf and one un 

 branched root which has no vascular tissue. These Ivs. 

 are called fronds by the botanist largely because Ivs. 

 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 oi i 

 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 I 

 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 tts. and the pistil a third 

 flower. Duckweeds are perennial plants. In 

 the autumn they fall to the bottom of the 

 ditch or pond, but rise again in the spring, 

 and increase in size. The allied genus Wolffia 

 contains the smallest flowering plants in 

 vegetable kingdom. There are about 11 si 

 cies of Duckweeds, widely scattered. 

 rhiza is commonly known in American bot 

 ies as Spirodela poly rhiza, but Spirodela 

 considered by Bentham and Hooker a si 

 genus of Lemna. The common Duckwe 

 occasionally infests the small lily ponds , 

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

 remedy is to flush the pond and see that cc 

 mon goldfish or carp are in sufficient numl 

 to clear off the remainder. 



A. Feins 7-11: roots several. 



polyrhiza, Linn. ( Sp irode la polyrhlza, 

 Schleid.). Also spelled polyrrhiza. Fronds 

 broadly ovate or orbicular, attaining 3 or 4 

 lines diam. B.B. 1:365. 



AA. Veins 1-5 : root solitary. 

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



trisulca, 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. 1:366. 

 3:800. 



BB. Fronds broadly ovate or orbicular, 



2 lines long.. 



minor, Linn. Figs. 1259-60. Fronds 

 ally cohering in 3's or 4's, rather thick, 

 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 

 since then attention has been more largely 

 given to hardier fruits. The growing of Lemon 

 trees is beginning again in lower Florida, 

 in sections freer from killing frosts, and al- 

 though soil conditions are rather unfavorable 

 to the cultivation of citrous trees, owing to 

 the rocky 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 

 isolated orchards of Lemons in southern 

 Florida, which have since entirely recovered 

 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 may be temporarily larger, Lemons 

 are constantly in demand, and the reward is correspond- 

 ingly certain. Orchards are usually set with budded 

 trees, about 20 by 25 feet apart. The young trees after 

 setting are advantageously mulched with grass or other 



