CONIBO. 292 CONIFERS. die Ucalayi River, northeastern Peru. For a long time they repelled the missionaries, but are now completely Christianized. In their daily life, however, they cling to their old customs, although they learn Spanish readily and prove valuable house servants. They live cliielly by boating, fishing, and gathering sarsaparilla. They paint their faces in red and' blue, and wear silver rings in their lips and noses. CONIC SECTIONS. Curves which may be fonned by various sections of a cone (q.v.). In the figure, which represents the two nappes of a right circular cone, AB, a sec- tion perpendicu- lar to the axis, is a circle ; CD, a section oblique to the axis, cutting all the elements of the conical surface on one side of the ver- tex, is an ellipse ; EF, a section parallel to the element CI, is a parabola ; and GH. I.J. a section cutting both nappes, gives the two liranches of an hyperbola. These curves were discovered by Menoechmus in the fourth century B.C., and were known for a long time as Menaechmian triads. The Cireeks extensively cul- tivated the theory of the conic sections. Since the invention of coildinate geometry (see Anal- ytic Geometry), new interest has attached to these curves, and the properties of conies form the basis of instruction in analj-tic geometry. See Circle; Ellipse; Par.a.bola; Hyperbola; Curves ; ilATiiEMATics. CONID'IA (Xeo-Lat. nom. pi., from Gk. k6- ms, l-otiis, dust). Aerial spores of fungi, usually formed in cliains or clusters upon the swollen end of a filament (the coiiidiophore) , and never borne in spore-cases (sporafifli'a) . See Fungi. CONIDIOPHORE. (Xeo-Lat. conidi inn + Gk. -06pos, -pharos, from ip^peiv, phrreiii. to bear). A fungal filament which bears conidia, one kind of asexual spores. See FinsTGi. CONIF'EE.iE (Lat. nom. pi. of conifer, cone- bearing, from conns, cone, Gk. kuvos, koiios + fcrre, to bear). The greatest of the four living groups of gynuiosperms. The species are all trees or shrubs, and are characteristic of the north and south temperate regions, being almost entirely ab- sent from the tropics. Prominent representatives of the group are the pines, spruces, hemlocks, firs, larches, cedars, cypresses, redwoods, junipers, arbor-vit;p. and vcw's. The habit of the trees is characteristic' a central shaft extending con- tinuouslv to the very top, while the lateral liranches spread horizontally, with diminishing length toward the top of the tree, resulting in a conical outline. Another peculiar feature is the 'needle leaf,' which seems to be poorly adapt- ed for foliage. It is very slender and firm, being well organized to endure cold. In some of the conifers, however, as in species of Podocar- pus, the leaves are quite broad and flat; while in others, as in the arbor-vita', they consist of closely appressed and overlapping disk-like bod- ies. As the leaves have no regular period of fall- ing, the trees are always clothed with them, and are commonly called evergreens. There are a few exceptions to this evergreen habit, however, as in the case of the common larch or tamarack, which sheds its leaves every season. The branches of conifers are apt to occur in two forms, as may be seen in the pines. There are the elongated a.xes, which bear only scales, known as the long shoots; and also sliort, spur-like, dwarf branches, which l)ear the clusters of needle leaves. This dis- position of the foliage leaves is by no means common to all conifers, or even to all ages of the pines. In many conifers, as in spruces and in seedling pines, the needles occur on the long shoots. The structure which gives name to the group is the cone-like strobilus which bears the seeds, and which sometimes becomes very large. This, when mature, consists of heavy overlapping scales, at the base of which, upon the upper side, the seeds are found. The strobili which are made up of the stamens are never so promi- nent or permanent, and hence are not usually no- ticed. The pollination of conifers is effected by llie wind, and hence the pollen is very light and ]iowdery. and is produced in enormous quanti- ties. In the pines the pollen-grains are assisted in this wind transportation by the development of a pair of wings, which are outgrowths from the outer coat of the spore. Sometimes strong winds carry the pollen far from the forests which produce it, and the fall of this -yellow pow- der in places in which the phenomenon is rare gives rise to accounts of 'showers of sulphur.' Structure. The tissues of the stems of coni- fers are very characteristic. The woody bundles are arranged to form a hollow cylinder, as in the dicotyledons, and hence are able to increase in diameter during each growing season. It is only the primitive bundles, however, which are made up of true vessels. All of the secondary bundles, which fonn the whole mass of wood, consist of tracheids, i.e. thick-walled cells resembling tnie vessels, but not fitted together end to end so as to form more or less continuous vessels. These tracheids are also distinguished, as in all g^"ni- nosperms, by bearing upon their walls bordered pits. i.e. thin spots which appear to be bounded by two concentric circles. They are also packed together very closely and with remarkable regu- larity, so that the wood is very uniform and fine- grained, and hence easily split. Classification. There are two great families of conifers, the Pinaeea? and the Taxaceje. The former has true cones, by whose scales the o-vules are concealed, and whose seeds ripen dry. In general, the cones ripen dry and hard, but some- times, as in junipers, they become pulpy, the ^^•hole cone forming the so-called 'berrs'.' This family (Pinace.T) is much the larger one, and contains four well-marked tribes. Chief among these are the Abietene, containing the pines, spruces, hemlocks, firs, larches, etc., the genus Pinus with its seventy species being by far the largest genus of conifers. The Cupresseoe con- tain the various cypresses and cedars; the Taxo- dieip contain the bald cypresses, redwoods, and their allies; while the Araucarite include the .raucarian or Xorfolk pines of the Southern Hemisphere. The other family, the Taxacese, has
