GROUP V. ANGIOSPERMJt;. 441 



different orders are dissimilar. In consequence of this so many com- 

 plicated forms arise that it is impossible to enumerate and name all the 

 combinations. As examples, the following will o'nly be mentioned : the 

 capitulate raceme, which consists of a number of capitula arranged in a 

 raceme ; it occurs in many of the Composite, e.g. Petasites : the spicale 

 capitulum, which consists of several spikes forming a capitulum, as in 

 the Scirpoidese : the spicate raceme, whi^h occurs in many Grasses, in 

 which the last branches of a compound raceme are spikes. 



B. C'ymose Inflorescences; the main axis produces one, two, or more 

 lateral branches rarely several at the same level below its apex, which 

 grow more vigorously than the main axis, and repeat the same type of 

 branching. 



These inflorescences are also termed definite because the growth of each 

 axis is arrested, by the development of a terminal flower, before that of 

 the lateral branch or branches which it bears. The simplest kind of 

 definite inflorescence is that in which the axis (peduncle) does not branch 

 but bears a single terminal flower. 



Cymose infloresences are also termed centrifugal, because the development 

 and expansion of the flowers begins with the primary axis, and occurs 

 successively in the axes of the second, third, and higher orders. 



I. In the simple cyme the ramification in the secondary and higher 

 orders follows the same type. 



(a) Without a pseud-axis. 



The cyme : beneath the terminal flower spring several three or more 

 lateral shoots of equal vigour, e.g. many Euphorbias. This inflorescence 

 greatly resembles the true umbel, and in fact cannot be distinguished 

 from a true umbel which has a terminal flower. The identification of an 

 inflorescence as belonging to the cymose type depends in many cases on 

 the fact that in the higher orders of branching the cymes are reduced to 

 dichasia. 



The dichasium (Figs. 10 and 11(7) consists of only two equal lateral 

 shoots arising at the same level below the terminal flower, and branching 

 in a similar manner. The successive false dichotomies commonly de- 

 cussate, e.g. Valerianella and the weaker inflorescences of many Euphor- 

 bias. 



(j3) With a pseud-axis. 



The scorpioid cyme (cincinnus and rhipidium): in this the lateral 

 branches occur alternately on opposite sides (Fig.ll A and B) : Boraginacese, 

 Crassulaceae, Iridaceae, Commelynaceae, etc. 



The helicoid cyme (bostryx and drepanium) : the lateral branches of the 

 successive ramifications always occur on the same side (Fig. 11 Z>) : this is 

 frequently found in Monocotyledons, such as Hemerocallis, Ornithogalum, 

 Alstroemeria, Juncacese. 



It has been ascertained, however, that in many cases (various Solanaceae 

 and Boragiiiacese) the so-called scorpioid cymes are monopodial : the axis 

 is therefore not a pseud-axis but a true one, and the inflorescence must be 

 regarded as a unilateral raceme. 



II. Compound cymose inflorescences arise on the one hand from the reduc- 



