CLASSIFICATION OF INFLORESCENCES. 



99 



start from one point at the sum- up of cj-mules, and so on. A Pamcle is a 



mit of the peduncle (Fig. 488). 

 B. With the rhachis elongated. 



4. The Spike, with the flowers, or 

 branches, if any, sessile or so 

 regarded (Fig. 4S9). 



5. The Catkin or Ament, a spike, 

 with slender rhachis and bear- 

 ing usuallj- staminate or pistil- 

 late flowers, crowded and sub- 

 tended by scales (Figs. 8, 12 

 and 15). 



6. The Raceme, similar to the 

 spike or ament, but having the 



flowers pedicelled (Figs. 490 

 and 491). 



When either the head or spike 

 possesses a thick, fleshy rhachis it 

 is called a Spadix (Figs. 492 and 

 493). 



Series S. 



Descending, Basipteal, Definite, Deter- 

 minate, Centrifugal or Cymose Forms, 



1. The Glomorule, corresponding to 

 the head in all respects save that 

 the central flower first develops. 



2. The Fascicle, similar to the glome- 

 rule except that the flowers are few 

 and loosely clustered. 



3. The Cyme. Similar to the corymb 

 or nmbel, save that the central 

 flower is the first to develop (Fig. 



494). I 



4. The Scorpioid Raceme. Similar to 

 the raceme, except that each suc- 

 cessive node and flower upward is 

 lateral to that next below. The 

 apex of the scorpioid raceme is cir- 



cinately coiled (Fig. 373B). 

 Before proceeding to consider certain 

 Special forms and modifications of the in- 

 florescences above defined, it should be re- 

 marked that most of the forms may be 

 compound. By this we mean that the 

 cluster is made pp of a number of branches 

 whose order of development is the same as 

 that of the elements of which they are 

 composed. That is, the raceme may pos- 

 sess a number of branches, each of which 

 is a smaller or secondary raceme, or if 

 not a raceme, at least a small inflores- 

 conco of the ascending or centripetal form. 

 Rimilarlv an umbel may be made up of 



compound raceme which assumes the form 

 of a pyramid. Any form of inflorescence 

 not a true panicle, but assuming the 

 shape of one, is styled Paniculate. 



Complex forms of inflorescence differ 

 from the compound in that the order of 

 development of the several flowers upon 

 a branch is of the opposite kind from that 

 of the several branches themselves. For 

 example, the Thyrsus or Thyrse is a pan- 

 iculate form in which the lowest branch is 

 the first to develop flowers, so that the 

 order of development of the branches is 

 ascending, but within a branch the ter- 

 minal flower will be the first to develop, so 

 that the order of development of its 

 flowers is descending. 



The term Hypanthodiuni has already 

 been defined In considering the forms of 

 the fruit, under IMnltiple or Collective 

 Fruits. The same term is applied to an 

 inflorescence yielding the collective fruit 

 of that name (Fig. 495). It is in reality 

 nothing" more than a head closely j.nb- 

 tended, surrounded or enclosed by an in- 

 volucre (a). The hypanthodiuni is char- 

 acteristic of the great family Compositae 

 and is of so much importance in classifi- 

 cation that its modifications call for spe- 

 cial attention. The Involucre should be 

 studied as to whether it is single, double 

 or multiple— that is, whether it consists 

 of one. two or more circles of scales; as to 

 whether these are equal in length or 

 whether the outer or inner are succes- 

 sively shorter; whether they are entirely 

 free and distinct, or ndnate by their bases 

 or connate by their margins; as to 

 whether they are appressed, or with more 

 or less of their apical portions recurved 

 or spreading; especially as to the general 

 form of the involucre as a whole, the 

 terms used being the same as those pre- 

 viously applied to the perigone, ana as to 

 the characters of the individual scales, 

 these being practically the same as those 

 which have already been considered in 

 connection with the leaves. The body 

 consisting of the combined tori of all the 

 flowers of the hypanthodium is called a 

 receptacle (b). It is to be studied as to 

 its beins" solid or hollow; as to its general 



branches, each of which is a smaller um- form, and especially the form of its upper 



bel, the Umbellule. A cyme will be made 



surface, whether concave, plane, convex, 



