72 



HISTORY OF TDE VEGETABLE KINGDOM. 



hilar or capitate, rounded like a little head ; 

 as in the cowslip, belladonna, and marvel of 

 Peru. Hemispherical, having the form of a 

 liemisphere ; as in the yellow henbane. Discoid, 

 flat, broad, and in the form of a shield; as 

 in the poppy. Claviform or club-shaped as in 

 jasione montana. Capillar or filiform, slender 

 and very elongated ; as in the maize. Linear, 

 naiTow and elongated ; as in the campanula; 

 and many caryophyllere. Trigonal, having 

 the form of a three-sided prism ; as in the wild 

 tnlip. Trilobate or three-lohcd, formed of three 

 rounded lobes ; as in the lily. Stellate, flat and 

 cut into several lobea, so as to resemble a star ; 

 as in the erieinew, and the genus Pyrola. Umbili- 

 caie, having a depression in its centre ; as in the 

 lily. Semilunar or crescent-shaped, as in the 

 yellow fumitory. 



Having described the parts of a single flower, 

 we shall now allude to the manner in which 

 these are placed on the stalk, and fi-equently 

 gi'ouped together. 



The term Inflorescence, is applied to designate 

 the general disposition or arrangement which 

 the flowers affect upon the stem, or the other 

 organs wliich support them. 



The flowers are said to be solitary when the 

 plant produces only one, or when they come ofi^ 

 one by one from different points of the stem, at 

 some distance from each other; as in the tulip 

 and the common garden rose. They are terminal 

 when situated at the top of the stem ; as in the 

 tulip. Lateral, when they spring from the sides 

 of the stems or branches. Axillar, when they 

 spring from the axilla of the leaves, as in the 

 greater periwinkle, and the ivy-leaved speedwell; 

 geminate, when they come off in pau-s fi'om the 

 same point of the stem, as in iiiola biflora ; ter- 

 nate, when they come off three together, as in 

 teuerium flavum; fasiicidate, when they come 

 off more than thi'ee together fi-om the same 

 point of the stem or branches, as in the cheny. 



1 . When the flowers are arranged upon 

 *• a common stalk or axis, which is sim- 

 ple or not branched, whether they be 

 sessile or pedunculate, and whetlier the 

 peduncle be straight or inclined, they 

 form a spike, and are accordingly des- 

 cribed as spiked, as in wheat, barley, 

 rye, the ribwort plantain, the black 

 currant, the bai'berry, and the genus 

 orchis. 



2. If the common peduncle branches 

 several times, and in an irregular manner, this 

 arrangement takes the name of raceme, and the 

 flowers are described as being racemose, as in 

 the vine. 



The characters which most authors have given 

 as distinguishing the spike from the raceme are 

 80 uncertain, that it is almost impossible to dis- 

 criminate between these two modes of inflores- 



cence. Thus, some say that the flowers are 

 sessile in the spike, and pedunculate in the 

 raceme ; and others, that the raceme is always 

 pendulous, and the spike erect. Perhaps the 

 best distinction is, that the axis of a spike is 

 always simple, whereas that of a raceme is al- 

 ways branched. 



3. When the common axis is erect, and the 

 peduncles are iiTCgularly divided into pedicels 

 bearing the flowers, if the whole assumes a 

 nearly pyramidid form, it obtains the name of 

 thyrsus, as in the lilac, the privet, and the horse- 

 chestnut. This species of inflorescence is closely 

 allied to the raceme. 



4. The flowers are said to be 

 disposed in a panicle, or to be 

 paniculate, when the common axis 

 is branched, and its secondary 

 divisions are greatly elongated and 

 widely separated. This species 

 of inflorescence belongs almost 

 exclusively to the graminese : 

 suoli, for example, are the male 

 flowers of the maize. 



5. The flowers are corymbose, 

 or are disposed in a corymb, when 

 the peduncles and pedicels spring 

 from different points of the upper 



I part of the stem, but all attain 

 nearly the same height ; as in 

 common milfoil. 



6. The cyme is produced, and 

 the flowers are said to be cymose, 

 when the peduncles proceed from 



the same point, the pedicels being unequal, and 

 coming off fr-om different points, but raising 

 all tlie flowers to the same height ; as in the 

 elder a ad cornel. 



7. The flowers are umbel- 

 late when all the peduncles 

 are equal, spring fi-om the 

 same point of the stem^ 

 diverge, and branch into 

 pedicels, which again come 

 off from the same point, so 

 that the general mass of the 

 flowers represents a convex 

 surface, like an expanded 

 umbrella. This disposition 

 is observed in the whole natural family of the 

 umbelliferffi ; for example, in the caiTot, hem- 

 lock, opoponax. The peduncles form collec- 

 tively an umbel ; and each group of pedicels con- 

 stitutes an umbellule. At the base of the umbel, 

 there is very frequently observed an involucre ; 

 and at the base of each umbellule an involucel ; 

 as in the carrot. At other times, the involucre 

 is wanting, while the involucels are present ; as 

 in chervil. Lastly, both involucre and involu- 

 cels may be absent ; as in pimpinella and sax- 

 ifraga. 



61. 



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