LEIOSOMA. 



[ 457 ] 



LEMON. 



under it many of the species of Cahthrix of 

 other authors. Endlicher cites only C. con- 

 fvrvicola, Ag., and another not British. 



It is a minute, glaucous, tufted plant, 

 formed of short, rigid, erect, subulate iila- 

 ments, and is common, epiphytic on marine 

 filamentous Alg.ie. 



BiBL. ]<:ndl. Gen. Plant. Supp. iii. No. 69 ; 

 Kiitz. Sp. Alg. 276; Harvey, Phyc. Br. 

 223, pi. 2(3 C. 



LEIOSO'MA, Koch.— A genus of Ori- 

 batea ; has the cephalothorax with plates, 

 the tarsi with three heterodactyl claws ; 

 two species. (Murray, Ec. Entom. 216, tig.) 



LEJEUX'IA, Libert.— A geiius of Juii- 

 germanniepe (Ilepaticte), containing several 

 rare British species, found in suhalpine dis- 

 tricts, viz. L. serpi/Uifolia, hamatifolia, mi- 

 nut issima, and cahiptnfuUa. The last is one 

 of the smallest of the British Jungerman- 

 nicae, and is remarkable for the peculiar 

 form of its leaves, which resemble the ca- 

 lyptra of a moss (figs. 392, 393). 



Fig. 392. 



Fig. 393. 



Lejennia ealyptrifolia. 



Fig. 392. Stem with calyptriform leaves, an immatnre 

 plant (on the right), and a burst sporange. 

 Magn. .5 diams. 



Fig. 393. A leaf of ditto. Magn. 25 diams. 



BiBL. Hook. Br. Jung. pis. 42, 43, 51, 

 62 ; Br. Fl. ii. pt. 1, 127. 



LEMANI'E.E.— A family ofConfervoi- 

 dese. Olive-coloured freshwater Algae, fila- 

 mentous, inarticulate, of cartilagineo-coria- 

 ceous substance, and compound cellular 

 texture. The /"ro??f7s branched, hollow, bear- 

 ing within at irregular distances whorls of 

 wart-like bodies consisting of tufted, sim- 

 ple or branched, necklace-shaped filaments 

 (fig. 394), arising from the inner wall of the 

 tubular frond, and finally breaking up into 

 elliptical spores. British genus : 



Lemnnin. Character the same as of the 

 family. Two species have been found in 



Britain, L. toruhsa, Ag., and L.fluviatilis. 

 They always grow in clear runniug streams. 

 Thwaites has made some interesting obser- 

 vations on the development of these plants. 



Fig. 394. 



A genus of 



Lemania torulosa. 



Section of frond, showing the tufts of fertile filaments. 



Magn. 50 diams. 



See CoMPSOGON. 



BiBL. Hassall, Alg. 68, pi. 7 ; Kiitz. Phyc. 

 gen. 271 ; Thwaites, Ann. N. H. 2 ser. i. 

 460 ; Wartmann, A7iat. d. Lemania., 1854 ; 

 liabenhorst, Alg. iii. 410 ; Sirodot, Lema- 

 neac. 1875 (23 pis.). 



LEMBA'DIUM, Perty. 

 Holotrichous Infusoria. 



Char. Body oval, flat, with a broad deep 

 buccal fossa, having an undulate membriine 

 on one side. 



L. bullinum ; marsh water. 



BiBL. Claparede et Lachm. Inf. 251 ; 

 Kent, Inf. 536. 



LEM'BUS, Cohn.— A genus of Holo- 

 trichous Infusoria. Free, elongate, mouth 

 ventral; a triangular ventral undulating 

 membrane. Four species ; marine. (Kent, 

 Inf. 547.) 



LEM'NA, L. — Duckweed. A genus of 

 aquatic Monocotjdedonous plants, remark- 

 able for their simplicity of structure, the ve- 

 getative system being replaced by a minute 

 leaf -like floating stem, with dependent root- 

 lets, furnished with a well-developed sheath 

 (pileorhiza) at the end. The lobes of the 

 stem bear two monoecious imperfect flowers, 

 and also propagate by bulbils formed in 

 the slits in the side of the lobes ; the 

 young bidbils formed in autumn sink when 

 the parent dies,, and rise again in spring. 

 Spiral vessels occur abundantly in L. 

 pohjrhiza ; they are sparingly present in 

 the rest. 



BiBL. Hook, and Arnott, Brit. Flor. ; 

 Schleiden, Bot. 229; Weddell {Wolffia), 

 Ann. Sc. Nat. 3 ser. 12, 155. 



LEMON, EssEXTiAi. oil or. — This is 

 sometimes used in the microscopic examina- 

 tion of pollen and other structures, which 

 are placed in it to render them more trans- 



