_graft._ A cutting inserted in another plant for the purpose of having it grow there. _gymnosperm_ (“naked seed”). A name applied to a group of plants (pines, spruces, cedars, and the like) in which the seeds are not contained in an ovary. _head._ A very dense globular or oblong flower-cluster in which the outer flowers open first; often applied to any dense flower-cluster. _herb._ A plant that never becomes woody and that dies to the ground, or dies entirely, in winter. _hilum._ The scar or spot where the seed was attached to its stalk. _hip._ The fruit of the rose, which is a hollowed torus containing the dry fruits or “seeds.” _homologous._ Related to, or with, in origin or structure. Thus, a tendril of grape is homologous with a branch; a tendril of grape is _analogous_ to a tendril of pea (similar in function), but not homologous, for one represents a branch (or flower-cluster) and the other represents a leaf. _host._ A plant or animal on which another organism grows or feeds. _hypha_ (plural _hyphæ_). The threads of the mycelium of a fungus. _hypocotyl._ The stem or internode below the seed-leaves. _hypogeal._ Said of seeds (as garden pea) in which the cotyledons remain under ground in germination. See _epigeal_. _imperfect flowers_ lack either stamens or pistils. _incomplete flowers_ lack one of the parts or series, as the calyx, corolla, stamens, or pistil. _indeterminate._ See _centripetal_. _indusium._ The scale or lid covering a sorus, in ferns and allied plants. _inflorescence._ Properly, the mode of flowering (page 160), but sometimes used in the sense of a flower-cluster. _involucre._ A set or whorl of leaves or bracts beneath a flower or a cluster of flowers; sometimes looks like an outer or extra calyx. _irregular flowers_ have some members of one or more of the series unlike their fellows. _key fruit._ See _samara_. _labiate._ Lipped; that is, divided into parts, as the lips of a mouth. Said usually of corollas that are lobed into two parts. _lateral._ On the side; as a flower or leaf borne on the side of a shoot rather than at its end. See _terminal_. _leaflet._ One of the divisions or parts of a compound leaf. _legume._ Like a follicle, but opening along both edges. In some cases, as in peanut, the pod does not actually open. _leguminous plants_ are those that bear legumes or true pods, as peas, beans, clovers, alfalfa, vetch, sweet pea, peanut, locusts, red-bud. _lenticel._ Very small spots or corky elevations on young twigs, marking the place of former twig stomates. _locule._ One cavity or “cell” in a pistil or anther. _loculicidal._ Said of capsules when the carpels or compartments open between the partitions. _mesophyll._ The parenchyma in the leaf. _micropyle._ The place on the seed at which the pollen-tube entered when the seed was forming (when impregnation took place).