LEPIDODENDRON. Ii4 LEPIDUS. LEPIDODEN'DRON (Xeo-Lat., from Gk. Af-if, Irpis, scale + dtrd/joi', dendron, tree). An important genus of extinct treelike club- mosses, the remains of which are abundant in rocks of Carboniferous age in many paits of the world. These plants, some of which grew to trees 75 to 100 feet in height, were gigantic ancestors of the modern club-mosses (Lycopo- dium),with which they have many points "of re- semblance. They grew in abundance in the swampy forests of Carboniferous coal-measure time, and their trunks, stems, leaves, and cones contributed largely to the vegetable mass which has been hardened into coal. They were stout trees with high woody trunks and central pith, and slender branches that bore closely set strap- shaped or awl-shaped leaves, and at the ends of the branches were borne large cone-like fruc- tifications (Lepidostrobus) comparable to those of the club-mosses, but much larger. Their well- known roots have been called Stigmaria, which name is also applied to the roots of other Car- boniferous plants. Lepidodendrons may be rec- ognized by the form and arrangement of the scars left on the trunks and stems by the fallen leaves. These scars are rlmmboidal or diamond- shaped in outline and are arranged diagonal!}- to Ihe a.is of the stem. In this respect they dif- fer from the scars of Sigillaria, which is "often found associated with Lepidodcndron, and which have a longitudinal arrangement parallel to the axis of the branch. Lepidodcndron appears first in the Lower Devonian rocks, was very abun- dant in the coal-measures of Carboniferous time, and became extinct in the Permian period. Sev- eral allied genera — Ulodendron. a tree-trunk from the Devonian ; Lepidophloios, Loraato- phloios; and Knorria, represented bj' decorti- cated stems in Permian rocks — are grouped to- gether in the family Lepidodendridse, which is eminently characteristic of Upper Paleozoic for- mations. BntLlOGEAPny. Solms-Laubach, Fossil Botany (Oxford, 1891) ; Lesquereux. •'Description of the Coal Flora of the Carboniferous Formation in Pennsylvania, and Throughout the United States," in Second Oeoloriical Survey of Penn- sylvania, Report of Progress — P, vols, i., ii., and V. (Harrisburg, 18S0-84) : Williamson, "Organ- ization of the Fossil Plants of the Coal Measures, part iii., Lycnpodiaeeie, Lcpidodendre.T. Sigil- laria?," in Philosophical Transnctious (London, 1872) ; David White. "Fossil Flora of the Lower Coal Measures of Missouri," in Monof/raph of Ihe United Stales Gcolorfiral Survey, vol. xxxvii. (Washington, 1899) ; Zittel, Schim'per, and Bar- Tois. Trnite de pnleontologic. part ii.. Paleophy- iologic (Paris. Munich, and Leipzig, 1891). LEPID'OLITE (from Gk.Ptir/f, lepis. scale + Mnc, lithos. stone). A mineral of the mica group, having a well-marked basal cleavage, pearly lustre, and varying in color from deep red to yellow or gray. It resembles niuscovite in chemical structure, but its alkali base is lithium instead of potassium. The amount of lithium present is about 5 per cent. Lepidolite occurs in granite and gneiss, especially in veins, where it is associated with tourmaline, cassiterite, spodumene, and muscovite. Some of the well- known localities for lepidolite are Auburn, Me.: Chesterfield. JIass.; ne.nr San Diego. Cal.: and Christiania. Xorway. The deposits^in Cali- fornia are exploited, and the mineral is sold to chemical manufacturers, who recover the lithium. See LiTHU'M. LEP IDOM'ELANE (from Gk. ?.emc, lepis, scale + /ie>.a(, melas, black). A variety of mica related to biotite. It is black, opaque, or trans- lucent, has an adamantine lustre, and differs from other micas cliietly in containing a large percentage of ferric iron. It occurs near Balti- more, Md., and Litchfield, Me., and at several localities in Sweden and Finland. LEP'IDOP'TERA ( Neo-Lat., from Gk. Actic, lepis, scale + -7ti>uv, pteron, wing). An order of insects including all those forms known as 'but- terllies' and "moths' (q.v.). They possess four wings, both body and wings being covered with scales, usually varialile in color, and those on the body resembling hair. The adult has mouth- parts incapable of biting and usually forming a long, coiled proboscis capable of protrusion. The metamorphosis is great and abrupt, and the pupa usually has its appendages cemented to the body. The duration of the pupa stage is longer than with other insects. The classification of the Lepidoptera is now in a condition of rapid change, authorities differing greatly in their con- ceptions of families. Fossil Lepidoptera are very much rarer than any other fossil insects, and except a couple of hawk-moths from the Jurassic of Solenhofen, Bavaria, have been found only in Tertiary rocks. The small Jlicrolepidoptera, especially the Tinci- d^, are represented l)y many sjjeciniens from the amber, and nearly all the other important fami- lies of moths have their Tertiary ancestors. The Oligoeene shales at Florissant," Colo., have fur- nished two most beautifully preserved specimens of butterflies (Prodryas and Barbarothea) . Con- sult: Von Zittel aiid Eastman, Textliook of Paleontoloay, vol. i. (London and Xew York, 1900) ; Scudder, Fossil Uutterilirs (Salem, 1875). See BlTTERFLIES A.ND MoTHS ; INSECT. LEPIDOSI'REN (Xeo-Lat, from Gk. IcttIq, lepis. scale + Xeo-Lat. Siren, a genus of am- phibians, from Lat. siren, Gk. aeipr/v, seiren, siren) . One of the three surviving genera of lung- fishes (Dipnoi). See Mcdfisii. LEPipOS'TKOBUS (Xeo-Lat., from Gk. XeTric, lepis, scale + arpdSoc, strobos, a whirl- ing round). The cone-like fossil fruit of Lep- idodcndron, found in the coal-measures of Car- boniferous age. See Lepidodendrox. LEP'IDO'TUS (Xeo-Lat., from Gk. ?fT»!u7dc, scaly, from '/e-idovf, lepidoun, to make scaly, from ^e-i'f, lepis, scale). An extinct genus of actinoplerygian ganoid fishes, allied to Semiono- tus, remains of which are abundant in the Meso- zoic deposits of Europe, India, and Brazil. See Semioxotus. I/EP'IDTJS. The cognomen of an illustrious Roman family of the .Emilia gens. The Lepidi played an important part in the history of Kome. from Marcus .Emilius Lepidus, consul in B.C. 285, to Manius .Emilius Lepidus. consul in A.D. 11. The chief members of the family were the following: (1) ]VL -EMrLns Lepidus "( ?-n.c. 152), who gained renown as a j'outh by slaying an enemy and saving a citizen's life, was one of three ambassadors sent by Rome to Egypt in B.C. 201 to govern the "realm of the infant Ptolemy the Fifth, Epiphanes; and although still a young man, Lepidus became the King's guard-
