_centripetal._ From the outside in; as a flower-cluster of which the outer flowers open first; an indeterminate cluster. _chlorophyll._ Leaf green. Chlorophyll is the pigment that gives the characteristic colour to plants. _cladophylla._ Stems that look like leaves, and function as leaves, as in asparagus and the florists’ smilax. _cleistogamous._ Applied to small flowers, usually hidden beneath the earth, that are little developed as to floral envelopes, and are self-fertilized; also to self-fertilization in flowers that do not open. _complete flowers_ have all the parts,—calyx, corolla, stamens, pistil. _corolla._ The inner row or series of flower-leaves, usually coloured, and often of irregular shape. It may be all one piece or of many pieces. _corymb._ A flattish flower-cluster in which the outermost flowers open first. _cotyledon._ A leaf of the embryo; seed-leaf. The embryo may have one cotyledon (monocotyledon), or two cotyledons (dicotyledon), or sometimes more than two. _cross-fertilization_ is fertilization by means of pollen produced in another flower. _cryptogam._ One of the group of flowerless or non-seed-bearing plants, as a fern, fungus, moss, seaweed. _cutting._ A shoot planted in soil or water for the purpose of making a new plant. _cyme._ A flattish or broad flower-cluster in which the innermost or terminal flowers open first. _decumbent._ Said of branches or stems that lop or lie over on the ground. _decurrent._ Said of a leaf that runs down on the stem, thereby not having a distinct petiole. _dehiscence._ The mode of opening, as of a seed-pod or an anther. _deliquescent._ Said of trees in which the leader or main trunk disappears at the tree top, forking into several or many main branches. _determinate._ See _centrifugal_. _dichogamy._ The condition when stamens and pistils in the same flower mature at different times; this prevents or hinders self-pollination. See _proterandrous_ and _proterogynous_. _diclinous._ Said of flowers that are imperfect,—lacking either stamens or pistils. _dicotyledon._ Having two cotyledons or seed-leaves. _digestion._ Change in the food materials whereby they may be transported, or used in assimilation. Starch is changed into sugar in the plant by a process of digestion. _dimorphous._ Of two forms; as flowers that bear two kinds of stamens. _diœcious._ Said of plants that bear stamens and pistils in flowers on different plants. _drupe._ A fleshy pericarp or fruit, containing a relatively large stone or pit, as peach, cherry, plum. _drupelet._ A very small drupe, particularly one comprising part of an aggregate fruit, as a drupelet of raspberry.