[Illustration: FIG. 371.--Diagram of a dichasium of _Ranunculus acer_: α_{1}, α^1, and β_{1}, β^1, bracteoles (the buds in the axils of the bracteoles, α and α^1, are continued antidromously). The flower has cyclic calyx and corolla, bub acyclic (8/21) stamens.] [Illustration: FIG. 372.--Diagram of an acyclic Ranunculaceous flower (only 3 stamens are indicated). The spiral of the sepals has a divergence of 3/5; that of the corolla and subsequent leaves 3/8.] Order 1. =Ranunculaceæ.= Nearly all are _herbs_ (except _Clematis_). The leaves are scattered (except _Clematideæ_), they have a large sheath with broad base (no stipules), and are most frequently palminerved with palmate lobes. The flowers are hypogynous, with most frequently a well pronounced convex receptacle (Figs. 374 _B_, 380), ☿, regular (except _Delphinium_ and _Aconitum_); their structure varies very much; in some the leaves are verticillate, in others arranged spirally; in others, again, both modes of arrangement are found. It is a characteristic feature that the various series of leaves (especially calyx and corolla) are not so distinct or so sharply divided as is usual. The leaves of the perianth are free, imbricate (except _Clematideæ_); stamens _numerous_, with most frequently extrorse anthers; gynœceum _free_, _apocarpous_ (except _Nigella_ and partly _Helleborus_), with 1 or several ovules (Figs. 373, 378, 379) borne on the ventral suture. The fruit is either a nut or a follicle (_Actæa_ has berries). The seed has a _large, oil-containing_ endosperm and a small embryo (Fig. 374). The main axis generally terminates in a flower, and the lateral axes branch in a cymose manner (Fig. 371). The flowers show the following differences in construction: VERTICILLATE (EUCYCLIC), _i.e._ constructed all through of alternating whorls: _Aquilegia_ (Fig. 370), _Xanthorhiza_, and sometimes _Eranthis_. SEMIVERTICILLATE (HEMICYCLIC) _i.e._ with sepals and petals in alternate whorls, and the others arranged spirally: _Ranunculus_ (Fig. 371), _Myosurus_, _Pæonia_ and several other genera entirely, or in certain species only. SPIRAL-FLOWERED (ACYCLIC) _i.e._ all the leaves are arranged spirally, so that sepals and petals do not alternate the one with the other, even though they are the same in number: _Adonis_ (Fig. 372), _Aconitum_, _Delphinium_-species, _Nigella_-species, _Helleborus_. The leaves of the calyx are in this instance arranged on a spiral of 2/5; those of the corolla on 2/5, 3/8, 5/13 or 8/21, and stamens and carpels likewise on higher fractions of the same series.