PHAXEROGAMIA 509 



number of members in a whorl the symbol oo is used denoting that the number is 

 large or indefinite. Such a formula may be further made to denote the cohesion 

 of the members of a whorl by enclosing the proper number within brackets, and by 

 placing a horizontal line below or above the number of the carpels the superior or 

 inferior position of the ovary is expressed. By placing an arrow before the formula 

 the dorsiventrality of the flower may be indicated, and by varying the direction of 

 the arrow it can be made clear whether the dorsiventrality is median, oblique, or 

 transverse. The formula for the Lily given above and for a number of other 

 flowers would thus take the following forms : 



Lily. P3 + 3, A 3 + 3, G (3). 



Buttercup. K 5, C 5, A oc , G oo . 



Laburnum, j K5, C5, A (5 -1-5), Gl . 

 Hemlock. K 5, 05, A 5, G(~2). 



Artemisia. K 0, C (5), A (5), G (2). 



Inflorescence. In many Angiosperms the single flowers are borne in large 

 numbers on special branch systems which differ in a number of respects from the 

 vegetative branch systems and are 

 termed INFLORESCENCES. In inflores- 

 cences, as in the vegetative region (cf. 

 p. 20), branches usually arise only 

 from the leaf-axils, the subtending 

 leaf being termed a BHACT. Leaves 

 borne on the axis of the flower itself 

 are known as BRACTEOLES. Bracts 

 and bracteoles may be classed to- 

 gether as BRACTEAL LEAVES (Fig. 



487). The MEDIAN PLANE passes 



through the axis and the middle line 



of the bract. The bracteoles, and 



the branches produced from their Kll . 4S7 ,.-,,,,., .,,, , ,.,,/ .,/; with bract 



axillary buds, may lie in this median (</) ami biacteoles (*). 



plane when they are said to have a 



MEDIAN POSITION, or more commonly they stand right and left of it, and their 



position is described as TI: VNSVKKSK (Fig. 487). 



According to the relative development of the main and lateral axes in an 

 inflorescence a distinction is made between RACEMOSE inflorescences, in which the 

 main axes are strongly developed and exceed their lateral shoots, and CYMOSE 

 inflorescences in which the lateral axes are more strongly developed and overtop 

 the main axis. The former may be also termed MONOPODIAL in contrast to 

 the SYMPODIAL or cymose type. The more frequent kinds of inflorescence are 

 enumerated below. 



I. Racemose Inflorescences. 



(rt) Lateral axes unbninched. 



1. RACEME ; stalked flowers borne on an elongated main axis (Figs. 488 A, 489). 



2. SPIKE; flowers sessile on an elongated main axis (Figs. 488 B, 490). A 

 spike in which the axis is thickened and succulent is termed a SPADIX ; a 

 spike which, after flowering or after the fruits have ripened, falls off as a 

 whole, is a CATKIN (Fig. 491). 



3. UMBEL ; flowers stalked, on a shortened main axis (Figs. 488 C, 492). 



