CICHOKIAOBAE. 61 



the segments were deep and narrow, as now seen in many a cam- 

 panulaceous flower. 



The theory of the origin of a ligule from a regular pentam- 

 erous deeply cleft or parted sympetalous corolla naturally pre- 

 supposes one of two distinct modes of transformation. It is 

 conceivable that, by the gradual congestion into a dense head of a 

 loose campanulaceous inflorescence, the deeply cleft corolla might 

 loose, one after another or little by little, all of its segments 

 save one ; but we should not expect a ligule thus derived to be 

 toothed at all at apex. And what is more, in the curious cam- 

 panulaceous genus Jasione, in which the flowers are crowded 

 into a dense head, involucrate like that of composites, there is 

 still no reduction or alteration of the corolla, this consisting of 

 five narrow-linear equal segments ; and the supposition that the 

 ligule of the chicory came about by elimination of segments 

 seems precluded. 



The other natural hypothesis, to me seems this : that there was 

 a cohesion of. the five segments beginning at the tip and pro- 

 ceeding downwards, until, by a natural tension, a rupture of the 

 incipient apical tube by the uppermost of the five sutures fav- 

 ored a complete union of the segments downwards by the other 

 sutures, until finally the five-toothed — equally five-toothed — 

 ligule become established. 



The anthological phases of another campanulaceous genus, 

 Fhyteuma, illustrate remarkably well the possibilities of the 

 descent of the chicory ligule along such a line, and by such 

 gradual modifications of a regular aud deeply five-parted corolla. 

 In some species of this genus there are the five linear rotate- 

 spreading segments of a kind not unknown in other related 

 genera. In some such it has long been noted by botanists that 

 before the full expansion of the five narrow segments, they 

 cohere lightly at tip, the expansion thus seeming to proceed from 

 the base in such wise that at the tips the segments are finally 

 forced apart by the tension to which they yield at last somewhat 

 suddenly. In others of this genus, the tips are never sundered 

 at all, but form a permanent five-toothed tube which reaches 

 down to the middle of the corolla, or near it, or below it, and 

 below this tubular part, the portion of the segments still 



