Mr. J. Ball on the genus Leoiitodon. 3 



to believe that the general form of the outline of the leaf is in a 

 great degree constant. 



The involucre furnishes chai'acters which are nearly as difficult 

 of definition as those derived from the leaves. The scales or 

 phyllaries vary much in their number and breadth, and in the 

 regularity of the order in which they are superimposed. In 

 some of the species of the section Asterothrix the involucre is 

 regularly imbricated with four or five rows of equidistant scales, 

 while in the section Apargia we have two rows of scales of nearly 

 equal length with a comparatively small number of short ac- 

 cessory scales at the base, and yet the series of intermediate forms 

 is so complete that it appears impossible to assign definite cha- 

 racters which shall apply exclusively to each species. 



The nature and amount of pubescence upon the leaves, stem 

 and involucre are next to be considered. In some species the 

 presence or absence of hairs seems to be determined by accidental 

 conditions, but in the section Asterothrix the presence of a rigid 

 stellate pubescence appears to be constant. This latter however 

 vanes much in its structure ; in some species the hairs are truly 

 stellate, consisting of a short stem crowned with a star, while in 

 others the hairs (which may be termed furcate) are divided at 

 the summit into two or three short branches not lying in the 

 same plane. These branches or spines are usually straight, but 

 sometimes recurved, forming minute hooks at the summit of the 

 hair. In a few instances short irregularly branched hairs are 

 seen to accompany the stellate pubescence. 



As a general rule, stellate, furcate, and simple hairs do not 

 occur together upon individuals of the same species, but I have 

 observed simple furcate hairs upon the same specimens oi L. has- 

 tilis, L., and L. Rosani, Ten., and I therefore doubt the propriety 

 of relying implicitly on the character of the pubescence for 

 permanent specific characters. In a few species the involucre is 

 occasionally covered with long silky fuscous hairs of a much 

 softer texture than those which are found on the leaves or stem ; 

 it may be doubted however whether these are constantly present 

 in any species of the genus. 



There are few genera of Cichoraceee in which the fruit varies 

 more in its form amongst the difl'erent species than in Leontodon. 

 In some species the achenium possesses a beak more than 

 equaling its own length, while in others the fruit is truly beak- 

 less. Owing to the difficulty of comparing dried specimens, from 

 the uncertainty which must exist as to the complete maturity 

 of the fruit, I have some hesitation in asserting my belief that 

 the relative length of the achenium and beak is not always con- 

 stant in the same species. The same observation may perhaps 

 be applied to the degree of roughness of the ribs of the fruit. 



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