PHYTOGENY. 233 



blossoms that constitute the thyrsus or synthetic form of 

 inflorescence. 



1190. The thyrsus or dense panicle is the whole 

 ramage or branch-fabric repeated in the involucrum; 

 it is therefore just as manifold as the former. 



1191. The inflorescence is still as complex as the 

 arrangement of the branches, because with every flower 

 the ramule dies off or ceases to grow, whereby very nu- 

 merous and strange relations are brought to light. 



1192. The involucrum corresponds to the scale-leaves 

 or bracts, and is therefore as a rule polypetalous. The 

 invomcral leaves stand upon a lower stage of develop- 

 ment, are for the most part only squamose or spathiform, 

 rarely divided or pinnate. 



1193. The involucral leaves necessarily stand, as 

 being the radical leaves of the flower, at the bottom of 

 the peduncles or flower-stalks ; each flower-stalk there- 

 fore has usually an involucral or bracteal leaf also. 



b. Calyx. 



1194. The repetition of the cauline or spathe-leaf in 

 the flower is the Calyx. It does not stand therefore at 

 the base of the peduncle, but towards its summit, and 

 is the external bud of the blossom ; it is mostly spathi- 

 form, rarely or but slightly cloven, and very rarely poly- 

 sepalous ; it is generally green like the leaves. Although 

 the calyx is no essential organ in itself, still it is rarely 

 wanting and is often itself the supporter of the corolla 

 and stamina. 



1195. As the calyx is more incomplete than the co- 

 rolla, so it has usually but three lobes, and if it has 

 five, then they are frequently placed irregularly. 



1196. The developmental stages of the calyx are also 

 three. Corresponding to the scale-like leaf or bract, it 

 is only squamiforrn, as in the catkins of the hazel and 

 fir-cones ; corresponding to the spathe-leaf, it is tubular 

 or unisepalous ; corresponding to the reticular leaf, it is 

 multisepalous, and mostly deciduous. 



1197. The tubular calyx exhibits likewise three stages 



