DEVELOPMENT OF THE MEMBERS' OF ONE BRANCH-SYSTEM. 



159 



figure by the thicker lines ; the terminal portions (indicated by thin lines) often 

 die off early; the thicker basal portions of the different ramifications which pro- 

 ceed from one another then commonly place themselves in a straight line, and 

 have the appearance of a connected whole, like a primary shoot to which the 

 terminal portions of each separate order of shoots are attached like lateral 

 branches ; the apparent primary shoot of the system is called the Sympodium or 

 Pseud-axis. The latter consists, in Fig. 128, B,e.g., of the pieces between 1-2, 2-3, 



Fig. i;8.— Cymose branchings represented dia^ammatically ; ^, B scorpioid (cicinal) cyme; C dichasium ; D helicoid (bostrj'- 

 choid) cyme; the numerals indicate the order of succession of the lateral shoots which spring from one another i. 



3-4, 4-5; the weaker terminal portions of the respective branches r, 2, 3, &c. are 

 bent sideways. A comparison of Fig. C with A shows that between a sympodially 

 developed and a spurious dichotomous system there is only this one point of 

 difference, that in the latter each branch produces not only one but two stronger 

 lateral branches. If in C one of the branches is imagined to be suppressed 

 alternately left and right, the form A results, which then is easily transformed 

 into B. 



Sympodial systems appear in two different forms, according as the lateral 

 shoots, the basal portions of which form the pseud-axis as they are continuously 

 developed, arise always on the same side or on different sides. 



If the sympodial ramification takes place always on the same side, e.g. always 

 to the right, as in Fig. 128, D, or always to the left, the whole system is called a 

 Helicoid Cyme (or bostryx) ; if, on the other hand, each branch which continues 



» [Some difficulty will probably be felt with regard to Fig. D, which stands for a helicoid cyme 

 in the text, but which is also identical with the scorpioid cyme of descriptive botany, and corresponds 

 to the specific name ' scorpioides ' given by Linnaeus to several plants in which it occurs. The term 

 scorpioid was introduced by A. P. De Candolle (Organographie, i. 415), to express a unilateral cyme 

 the undeveloped portion of which is usually rolled up. This is the characteristic inflorescence of the 

 Borraglnacea^, amongst which Myosotis has long been distinguished as ' scorpion grass' on this account. 

 Bravais (Ann. de Sci. Nat. 2^. ser. vii. 197) distinguished the helicoid cyme, which he defined as 

 having the successive flowers ranged in a spiral round the pseud-axis, while in the text above they are 

 all placed in the same plane. Bravais amended De Candolle's definition of the scorpioid cyme by 

 pointing out that the flowers are in two rows parallel to the pseud-axis. — Ed.] 



