INTRODUCTION TO BOTANY. ix 



partial are also applied to involucres (64) when similarly situated. The 

 word bracteole is sometimes given to the uppermost bracts, when much 

 smaller or very different from the lower ones. 



§ 8. Inflorescence. 



57. The Inflorescence of a plant is the arrangement of the flowering 

 branches, and of the flowers upon them. An inflorescence is a flowering 

 branch, or the flowering smnmit of a plant above the last stem-leaves, with 

 its branches, bracts, and flowers. 



58. A flower or an inflorescence is terminal when at the siunmit of a 

 stem or leafy branch ; axillary, when in the axil of a lateral leaf, 



59. A peduncle, or flowerstalk, is the stalk either of a solitary flower or 

 of an inflorescence ; in the latter case it may be either simple or branched. 

 A pedicel is the ultimate branchlet of an inflorescence, supporting a single 

 flower. 



60. A scape is a peduncle that proceeds from the rootstock, or from so 

 near the base of the stem as to appear radical, provided always that it 

 bears no leaves at all, or that the leaves are reduced to mere scales or 

 bracts. 



61. The inflorescence is centrifugal, when the terminal flower opens 

 first, and those on the lateral branches are successively developed ; centri- 

 petal, when the lowest flowers open first and the main stem continues to 

 lengthen, developing fresh flowers. Both these kinds of inflorescence may 

 be combined on the same plant ; the main Tsranches may be centripetal, 

 and the flowers on the lateral branches centrifugal, or vice versa. 



62. An Inflorescence is, 



a Spike, or spicate, when the flowers are sessile along a single un- 

 branched axis, called the rachis. Catkin is the name given to 

 the spicate inflorescence of several trees whose flowers are 

 reduced to scaly bracts or are very imperfect ; as in the Oak, 

 Willow, etc. Spadix is a fleshy spike round which is rolled a 

 single large bract, or S2mtke, as in the Arum plant {Richardia 

 ^thiopica). The inflorescence of a Palm is usually a branching 

 spadix. 



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

 a single unbranched axis, also often called the rachis. 



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

 each bearing two or more flowers. 



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

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

 conical axis on which the flowers of a head, or capitulum, are 

 seated, is called the receptacle — a term also given to the torus or 

 thalamiimi of a single flower. 



an Utnbel, or umbellate, when several branches or pedicels spring 

 from the same (apparent) point, i. e. from an axis reduced to a 

 point. (It is essentially the same as a raceme with the axis sup- 

 pressed ; or as a head, with long-stalked flowers.) An umbel is 

 said to be simple, when each of its branches or ra?/s supports a 

 single flower ; compound, when each ray supports a partial 

 umbel, or umbellule. 



a Corymb, or corymbose, when the branches or pedicels starting from 

 several points on a short, but not suppressed axis, all attain 

 nearly the same level. It is a flat-topped or fasti yiate panicle 

 or short raceme. 



a Cyme, or cymose inflorescence, is a centrifugal panicle, and is fre- 

 quently corymbose. The terminal flower opens first. The 



