OUTLINES OP BOTANY. XXlll 



that is to say, the portion of the flowering branch from the last stem-leaf 

 to the flower, or to the first ramification of the inflorescence, or even up to 

 its last ramifications ; but the portion extending from the first to the last 

 ramification or the axis of inflorescence is often distinguished under the 

 name of rachis. 



69. A Scape or radical Peduncle \s a leafless peduncle proceeding from the 

 stock, or from near the base of the stem, or apparently from the root itself. 



70. A Pedicel is the last branch of an inflorescence, supporting a single 

 flower. 



71. The branches of inflorescences may be like those of stems, opposite, 

 alternate, etc. (32, 33), but very often their arrangement is different from 

 that of the leafy branches of the same plant. 



72. Inflorescence is 



centrifugal, when the terminal flower opens first, and those on the 

 lateral branches are successively developed. 



centripetal, when the lowest flowers open first, and the main stem 

 continues to elongate, developing fresh flowers. 



73. Determinate inflorescence is usually centrifugal. Indeterminate 

 inflorescence is always centripetal. Both inflorescences may be com- 

 bined on one plant, for it often happens that the main branches of an 

 inflorescence are centripetal, whilst the flowers on the lateral branches 

 are centrifugal ; or vice versa). 



74. An Inflorescence is 



a Spike, or spicate, when the flowers are sessile along a simple undi- 

 vided axis or rachis. 



a Baceme, or racemose, when the flowers are borne on pedicels along 

 a single undivided axis or rachis. 



a Panicle, or paniculate, when the axis is divided into branches bear- 

 ing two or more flowers. 



a Head, or capitate, when several sessile or nearly sessile flowers are 

 collected into a compact head-like cluster. The short, flat, convex or 

 conical axis on which the flowers are seated, is called the Receptacle, a term 

 also used for the torus of a single flower (135). The very compact flower- 

 heads of Composites are often termed compound flowers. 



an Umbel, or umbellate, when several branches or pedicels appear to 

 start from the same point and are nearly of the same length. It differs 

 from the head, like the raceme from the spike, in that the flowers are not 

 sessile. An umbel is said to be simple, when each of its branches or rays 

 bears a single flower ; compound, when each ray bears a partial umbel or 



a Corymb, or corymbose, when the branches and pedicels, although 

 starting from different points, all attain the same level, the lower ones 

 being much longer than the upper. It is a flat-topped or fastigiate 

 panicle. 



a Cyme, or cymose, when branched and centrifugal. It is a centrifu- 

 gal panicle, and is often corymbose. The central flower opens first. The 

 lateral branches successively developed are usually forked or opposite 

 (dichotomous or trichotomous), but sometimes after the first forking the 

 branches are no longer divided, but produce a succession of pedicels on 

 theii upper side forming apparently unilateral centripetal racemes ; whereas, 

 if attentively examined, it will be found that each pedicel is at first ter- 

 minal, but becomes lateral by the development of one outer branch only, 



