ARRANGEMENT, DURATION, AND VARIETIES OF BRACTS. 193 
Sometimes when the bracts are situated in a whorl imme- 
diately below the calyx, it is difficult to determine whether they 
should be considered as a part of the calyx or as true bracts ; 
thus, in most flowers of the Mallow order (jig. 395), and many 
of the Pink (fig. 474, b) and Rose orders (fig. 396), we have 
a circle of leafy organs placed just below the calyx, to which the 
term of epicalyx has been given by many botanists, but which 
properly comes under the denomination of involucre (page 194). 
Almost all inflorescences are furnished with bracts of some 
kind or other ; it frequently happens, however, that some of 
the bracts do not develop axillary flower-buds, just in the same 
manner as it occasionally happens that the leaves do not produce 
leaf-buds in their axils. In some cases the non-development of 
flower-buds in the axil of bracts appears to arise simply from 
accidental causes ; but in others it occurs as a regular law, thus 
in the Purple Clary (Salvia Horminwm), and the common Pine- 
apple (fig. 292), there are a number of bracts without flower- 
buds placed at the apex of the inflorescence. Such bracts are 
called empty. When bracts are absent altogether, as is usually 
the case in the plants of the natural order Cruciferze, and those 
of the Boraginacez, such plants are termed ebracteated ; when 
bracts are present the inflorescence is said to be bracteated. 
Arrangement and Duration of Bracts.—Bracts follow the same 
laws of arrangement as true leaves, being opposite, alternate, or 
whorled, in different plants. The bracts of the Pineapple fruit 
(fig. 292), and those of Fir cones (figs. 293 and 420), show in a 
marked manner a spiral arrangement. 
Bracts vary in their duration; thus when they fall imme- 
diately, or soon after the flower-bud expands, they are said to be 
deciduous ; or when they remain long united to the floral axis, 
they are persistent. In some plants they persist and constitute 
a part of the fruit; thus, in the Hazel-nut and Filbert they 
form the husk (fig. 401), in the Acorn they constitute the cup 
(fig. 400), and in the Hop-fruit (jig. 421), in the Fir-cones 
(figs. 293 and 420), and Pineapple (jig. 292), they persist as 
membranous, woody, fleshy, or scaly appendages. 
Varieties of Bracts.—Bracts have received special names 
according to their arrangement and other characters. Thus the 
bracts of that kind of inflorescence called an Amentum or 
Catkin (see page 202), as seen in the Willow (fig. 416), Oak, 
Hazel (fig. 397), Birch, and other plants, are usually of a scaly 
nature, and are termed squame or scales; or the bracts are 
described as squamous or scali;. The bracts of the pistillate 
flowers of the Hop (fig. 421) are of like character. 
When a circie or whorl of bracts is placed around one flower, 
as in the Marsh Mallow (fig. 395) and Strawberry (fig. 396) ; or 
around anumber of flowers, as in the Carrot (jig. 398) and most 
other Umbelliferous plants, they form what is termed an invo- 
lucre. Insome Umbelliferous plants, as for instance the Carrot, 
) 
