INFLORESCENCE. 



69 



332. The peduncle is subject to endless modifications. T7o find it sometimes 

 excessively lengthened, again very short or -wholly wanting; very slender or very 

 thick. In coxcomb its branches are blended into a thick, fan-shaped mass; in 

 butch er's-broom it expands into the form of a green leaf, and in the linden-tree into 

 a seal-like bract. In Xylophylla it is foliaccous, bearing flowers along its margins. 



333. Bracts. The brandies of the inflorescence arise from tho 

 axils of reduced leaves, called hracts. These leaves, still smaller, grow- 

 ing upon the pedicels, are called bracteoles. 



334. The bracts are usually simple in outline and smaller than tho 

 leaf, often gradually diminishing to mere points, as in Aster, or even 

 totally suppressed, as in the Crucifcree. 



335. In color they are usually green, often colored, sometimes bril- 

 liantly, as in painted-cup. Sometimes they arc scale-like, and again 

 they arc evanescent membranes. 



336. The spathe is a large bract formed in some of the monocotyle- 

 dons, enveloping the inflorescence, and often colored as in the Arum, 

 Calla, or membranous as in the onion and daffodil. Bracts also con- 

 stitute an 



101 103 133 



Bracts (V&, b,). ISO, Cornus Canadensis, with an involucro of 4 colored bracts. 103, Ilepatiea 

 triloba, with an involucre of 3 green bracts. 191, Calla palustris, with a colored spathe of ono 

 bract. 



337. Involucre when they arc collected into a whorl or spiral 

 group. In tho Phlox, Dodecatheon, and generally, the involucre is 

 green, but sometimes colored and pctaloid, as in dogwood and Euphor- 

 bia. Situated at the base of a compound umbel, it is called a general 

 involucre, at the base of a partial umbel it is a partial involucre or in- 

 volucel, both of which arc seen in the uinbellifera. 



338. In the composite, where the flowers are crowded upon a com- 

 mon torus, forming what is called a compound flower, an involucre com- 

 posed of many imbricated scales (bracts) surrounds them as a calyx 

 surrounds a simple flower. The chaff also upon the torus are bracts 

 to which each floret is axillary. 



