ORGANS AND SYSTEMS OF GROANS. 183 



1. Scorpioid cyme (cicinnus, cyme, half cyme) ; secondary axes 

 are arranged alternately to the right and left. Example : Drosera. 



According to GOBEL'S investigations, the inflorescence of the 

 JSorraginece cannot be included here. It is rather a dorsi-ventral 

 raceme. 



2. Helicoid cyme (bostrychoid cyme, bostryx) ; secondary axes 

 all on the same side of the primary axis. Example : Hypericum 

 perforatum. 



3. Dichasium. This is really a slight deviation from the panic- 

 ulose type in that the primary axis divides into two equally strong 

 branches (Silene). 



Different types of inflorescence may occur on the same plant, 

 or the same type may be duplicated on the same stalk. In this way 

 complex inflorescences are formed. Umbelliferce have double um- 

 bels. Among GraminecB small spikelets unite to form a panicle 

 (oats), or again unite to form a spike. . 



B. RANK AND SUCCESSION OF SHOOTS. 



Above the statement was made that there was a difference in 

 the " rank " of various organs in a system as well as a difference in 

 " order." While the orders are determined by the origin and de- 

 velopment of members, the difference in rank of various members 

 of a system depends upon physiological inequality. As a rule, each 

 member develops secondary or lateral members of the same or next 

 higher rank. The arrangement of branches in the inflorescence 

 absolutely necessary to the development of flowers is usually differ- 

 ent from those branchings not necessary, usually known as " acces- 

 sory branches " (Bereicherungsprosse). 



Case 1. The primary axis, or axis of the first order, bears an 

 apical flower : " uniaxial" flowers, one rank. Example : Helleborus 

 niger. 



Case 2. A member of the second order is necessary to develop 

 a flower: "biaxial" plants, two ranks. Example: Paris quadri- 

 folia allows the axis of the first order to grow beneath the soil as a 

 rhizome bearing cataphyllary leaves. In the axil of the third cata- 

 phyllary leaf there is formed a vertical member of the second order 

 which terminates in a flower (A. BRAUN). 



Case 3. Flowers are formed on members of the third order: 

 " triaxial " flowers, three ranks. Example: Lathyrus. The mem- 



