BOTANY. 23 



Tlie peduncle is variously formed, experiencing greater modifications than 

 the petiole. Sometimes the axis is shortened, so as to exhibit a flattened 

 form, with flowers scattered over the surface. Here it becomes a receptacle, 

 phoranthium, or clhnanthium. Sometimes the peduncle is abortive, am! 

 becomes converted into a tendril ; at others, it is expanded and hollowed 

 out at the apex. The extremity of the peduncle is the (halanuis, or 

 torus. 



Inflorescence is of two kinds ; one where the lower flowers on the stem 

 are produced first, the other where i\\(iy are last to appear. In the first 

 kind of inflorescence, called indefinite, or axillary, the axis continues to grow 

 and to develope new leaf buds, the upper being always less advanced than 

 the lower ; or, if the axis be shortened, so that the peduncles stand crowded 

 together, the central flowers are less advanced than the external. Th(; 

 expansion of the flower is thus centripetal. 



The simplest form of indefinite inflorescence is, where single flowers are 

 produced in the axils of the ordinary leaves. The difi'erent subdivisions and 

 their relative lengths give rise to a great variety of terms. When the 

 primary peduncle is elongated, and gives off nearly equal pedicels, each 

 bearing a flower, we have a raceme, as in the currant, and a panicle when 

 the pedicels of the raceme are themselves branched. If the central 

 peduncles of a dense panicle are longest, a thyrse is produced. A corymb 

 is where the lower pedicels on a peduncle are elongated, so that all the 

 flowers on the different pedicels are nearly in one plane ; the corymb may 

 be simple or compound, the secondary axis again subdividing in the lattei- 

 case. When the pedicels are very short or absent, so as to render the 

 flowers sessile, a spike is produced : this, when producing unsexual flowers, 

 as in the willow, becomes an amejitum, or catkin. It may also be succulent 

 or pulpy, with the flowers invested by a sheathing bract or spathe, as in 

 Arum ; it is then called a spadix. A spike bearing female flowers only, and 

 covered with scales, is either a strohilus, as in the hop, or a cone, as in the 

 pine. 



When the primary axis is depressed, instead of being elongated, other 

 forms are exhibited. Should the pedicels all spring' from nearly the same 

 ])oint on the axis, we have an umbel; when numerous flowers are placed 

 on a nearly flat receptacle, and either sessile or nearly so, a capitulum, 

 anthodium,, or calathium is formed, as in the dandelion ; Avhen the surface is 

 more convex this is called a fflomerule. A receptacle may be concave, ami 

 inclose the flowers, as it Avere ; such an arrangement is called a hypante- 

 odiimi, and is seen in the fig. 



In definite inflorescence, Avhere the flower buds are all terminal, tlie 

 main axis is first terminated by a blossom which terminates its growth. 

 This gives a solitary terminal flower, as in the Tulip. Further development 

 can take place only by the production of axillary branches, which can 

 spring from the primary peduncle only when it is fiu-nished Avith bracts, from 

 whose axils they may arise. The order of floAvering is therefore from the 

 apex doAvuAvards, or descending- (the reverse of the indefinite forms) : 

 centrifugal, or from the centre outAvards, if the blossoms are on a level 



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