INTRODUCTION XXlll 



has a long peduncle and short pedicels ; whilst the Primrose has 

 a very short peduncle buried among its leaves, and long pedicels. 



Among other chief varieties of the inflorescence are the 

 following : — The spike^ an elongated axis with sessile flowers as in 

 the Plantains (p. 402). The spadix^ a spike, with a fleshy axis or 

 peduncle, as in Lords-and-ladies (p. 507). The caikin, generally 

 described as a deciduous spike, as in the Hazel and the ^\'illows 

 (p. 452). The raceme, an elongated axis with stalked flowers, as 

 in INIignonette (p. 60). A corymb, which only differs from a 

 raceme in the lower pedicels being longer, so as to bring all the 

 flowers nearly to a level, as in the ^^'allflower. A head, in which 

 many small sessile flowers, or florets, as they are called, are 

 crowded together on the expanded apex of tRg peduncle, Avhich is 

 then termed the common receptacle. This occurs in the Scabious 

 (p. xxii) and in all the great order ComposiicE, the Daisies, Dande- 

 lions, Thistles, &:c., which Linnaeus called "compound flowers." 

 An umbel, in which many flowers-stalks radiate from a common 

 centre, as in the Ivy (p. 225). 



If an influrescence is branched more than once it is termed 

 compound. Thus an ear of Wheat is a compound spike or spike of 

 spikelcts, and the Carrot, Parsnip, Hemlocks, and most other 

 members of the Order UmbelliperLE, have compound umbels. 



^^■hen the terminal or central flower in a cluster opens first the 

 inflorescence is called a cyme. Among the various forms of cyme 

 are \\\ft fascicle, a crowded cluster of nearly sessile flowers, as in the 

 Pinks (p. 71), and the verticillaster or false whorl, where two such 

 clusters occur in the axils of opposite leaves, as in the Dead 

 nettles and other members of the order Labiatce (pp. 379 — 401). 



Br-\cts are small leaves which are generally to be found below 

 the flower. The inflorescence of the Cruciferce is remarkable for 

 being without any, or ebracteate. Sometimes they are mere mem- 

 branous scales, as in the Cranesbills ; or they may be leaf-like, as 

 in the Anemones ; or petaloid, resembling the petals in colour 

 and texture, as in the Wild Hyacinth, ^^'hen in one or more 

 whorls below the inflorescence they are called the involucre (from 

 the Latin involucrum, an envelope). In the Dandelion the in- 

 volucre consists of two whorls of green bracts, those of the outer 

 whorl reflexed (p. 291). In the Knapweedsjhe numerous bracts 

 of the involucre are membranous, dark brown, and arranged 

 imbricately, i. e. o-serlapping like roof-tiles. , All Compoiifa and 

 most Umbelliferce have involucres. An involucre persisting in the 

 fruit stage, like the leafy husk of a Hazel-nut or the ''cup" of an 

 Acorn, is termed a cupule. This structure gives its name to the 

 Order Cupuliferce. 



