_Descending_, tending gradually downwards. _Descending axis_, the root. _Desmos_, Greek for things connected or bound together. _Determinate Inflorescence_, 72. _Dextrorse_, turned to the right hand. _Di- Dis_ (in Greek compounds) two, as _Diadelphous_ (stamens), united by their filaments in two sets, 99. _Diagnosis_, a short distinguishing character or descriptive phrase. _Dialypetalous_, same as polypetalous. _Diandrous_, having two stamens, &c. _Diaphanous_, transparent or translucent. _Dicarpellary_, of two carpels. _Dichlamydeous_ (flower), having both calyx and corolla. _Dichogamous_, _Dichogamy_, 116. _Dichotomous_, two-forked. _Diclinous_, having the stamens in one flower, the pistils in another, 85. _Dicoccous_ (fruit), splitting into two _cocci_ or closed carpels. _Dicotyls_, 23. _Dicotyledonous_ (embryo), having a pair of cotyledons, 23. _Dicotyledonous Plants_, 23, 182. _Didymous_, twin. _Didynamous_ (stamens), having four stamens in two pairs, 100. _Diffuse_, spreading widely and irregularly. _Digitate_ (fingered), where the leaflets of a compound leaf are all borne on the apex of the petiole, 58. _Digynous_ (flower), having two pistils or styles, 105. _Dimerous_, made up of two parts, or its organs in twos. _Dimidiate_, halved; as where a leaf or leaflet has only one side developed. _Dimorphism_, 117. _Dimorphous_, _Dimorphic_, of two forms, 117. _Diœcious_, or _Dioicous_, with stamens and pistils on different plants, 85. _Dipetalous_, of two petals. _Diphyllous_, two-leaved. _Dipterous_, two-winged. _Diplo-_, Greek for double, as _Diplostemonous_, with two sets of stamens. _Disciform_ or _Disk-shaped_, flat and circular, like a disk or quoit. _Discoidal_, or _Discoid_, belonging to or like a disk. _Discolor_, of two different colors or hues. _Discrete_, separate, opposite of concrete. _Disepalous_, of two sepals. _Disk_, the face of any flat body; the central part of a head of flowers, like the Sunflower, or Coreopsis, as opposed to the ray or margin; a fleshy expansion of the receptacle of a flower, 113. _Disk-flowers_, those of the disk in Compositæ. _Dissected_, cut deeply into many lobes or divisions. _Dissepiments_, the partitions of a compound ovary or a fruit, 108. _Dissilient_, bursting in pieces. _Distichous_, two-ranked. _Distinct_, uncombined with each other, 95. _Dithecous_, of two thecæ or anther-cells. _Divaricate_, straddling; very widely divergent. _Divided_ (leaves, &c.), cut into divisions down to the base or midrib, 55. _Dodeca_, Greek for twelve; as _Dodecagynous_, with twelve pistils or styles, _Dodecandrous_, with twelve stamens. _Dodrans_, span-long. _Dolabriform_, axe-shaped. _Dorsal_, pertaining to the back (_dorsum_) of an organ. _Dorsal Suture_, 106. _Dotted Ducts_, 148. _Double Flowers_, where the petals are multiplied unduly, 79. _Downy_, clothed with a coat of soft and short hairs. _Drupaceous_, like or pertaining to a drupe.