96 



ESSENTIALS OF VEGETABLE PHARMACOGNOSY. 



cycle or spiral — that is, the number of de- 

 grees between such leaves will equal that 

 fractional part of 3G0 degrees. 



As to the direction which the spiral 

 takes, it may be either fi'oni right to left 

 or from left to right. It is supposed that 

 each kind of plant, at least of the higher 

 classes, produces two forms or "castes, 



»> 



^'g'*S5; 



depending in some not yet perfectly de- 

 termined way upon the relative positions 

 of the respective ovules from which they 

 orisiuate. The tendency of these two 

 castes to manifest their growth or devel- 

 opment in opposite directions has been 

 called Antidromy.* Among numerous 

 other phenomena attributed to antidromy 

 is this starting of the leaf -spiral in oppo- 

 site directions in plants of the two castes 



of any species with this form of phyllo- 

 ta xy. 



Occasionally leaves appear to be irreg- 



tered, and the explanation is different in 

 different cases. When a stem is so short- 

 ened that the leaves are crowded upon it 

 in the form of a regular rosette, as in the 

 house leek, the arrangement is called 

 Tufted. When similarly short, but the 



leaves few and irregularly crowded in ^ 

 little bunch, the arrangement is Fasci- 

 cled. 



The two regular forms of leaf arrange- 

 ment above described can be traced in 

 greater or less perfection through floral 

 bracts and involucres and into, and in 

 many cases partly or wholly through, the 

 flower itself. While such arrangement in 

 the flower is in many cases entirely ver- 

 ticillate, and in most cases partly so, it 

 has been quite clearly shown that many 

 flowers have certain of their parts ar- 

 ranged upon the spiral plan. 



ANTHOTAXY. 



That part of a stem or branch which 

 bears the flowers, or the flower when 

 solitary, is more or less distinctly modi- 

 fied in form, surface and extent and char- 

 acter of branching, and frequently also 

 in the direction taken in the arrangement 

 of its parts. In connection with its 

 flowers it is called the Infloresence. The 

 portion of an inflorescence which is be- 

 low its lowest point of branching or 

 flowering, or below the flower when soli- 



ularly disposed upon the stem— that is, tary, is called the Peduncle (Figs. 485 and 



they are not whorled, nor does the law of 489a). This name is also applied to the 



alternate phyllotaxy appear to apply to 

 tUem. This arrangement is called Scat- 



*See article by Professor George Maclos- 

 kie. In Bull. Torr. Bot. aub, XXII.. 379. 



corresponding jwrtion of a branch of an 

 inflorescence if that branch bear more 

 than one flower, it being in that case a 

 Secondary Peduncle (Fig. 494d), If the 



