3. The Bract Region. Bracts. — These organs may bo regarded as 

 intermediate between the vegetative and reproductive ; being as- 

 similated to the t'oriner whenever they are green, and more or less 

 foliaeeous ; but allied to the latter, when pt'taloid in character. 



The homology of bracts and bractcoles is various. In the first 

 place, they may be stipular, as in Alaciiiolia, strawberry, Hcrniaria, 

 and violet, for the two minute bractcoles on the peduncle of the 

 violet would seem to correspond in their acuminate and dentate 

 characters with the stipules found on the rhizome, the leaf be- 

 longing to them having been suppressed. Another case is seen in 



Ainelanchier, as figured in De Candolle's 



Organ. 



,'* in which 



the ciliated bracts beneath the flower are similar in every respect 

 to some of the stipules, of which the author observes :f " On 

 y voit en s les stipules, qui en s' prennent une forme semblable aux 

 bracteoles ^5." The stipules being dimorphic, the outer stipular 

 bud-scales (alluded to as s) being lanceolate and glabrous, the 

 bracteiform stipules («') as well as the bracteoles {h), being almost 

 acicular and ciliate. The epicalyx of Fragaria appears to be due 

 to ten stipules coherent in five pairs.;]: 



More frequently bracts are petiolar, as is so well seen in Helle- 

 horus viridis, which affords a completely graduated series, from the 

 true pedate leaf to an oval acute bract, by gradual suppression of 

 the segments, and a dilatation coupled with a shortening of the 

 petiole. 



On the other hand, it may be the leaf-blade more or less reduced 

 in size which constitutes the bract. Such is the case Avith 

 Geranium, as e.g. G. lucidum, in which the radical leaves have 

 long petioles, the cauline being much shorter, while the bracts have 

 none, but retain the sub-orbicular form of the lamina. In species 

 of Ranunculus with divided laminae the bracts have the appearance 

 of sessile segments gradually reduced in dimensions and number as 

 the flowers are approached. 



Lastly, the bract may be the whole leaf, whether the latter be 

 normally sessile or petiolate, according to the species, but simply 

 reduced in size. When this is the case, the transition from leaves 

 to bracts is usually so gradual that it is impossible to draw any line 

 of demarcation. The shortly petiolate leaves of species of Epdo- 

 bium and of Pedicularis racemosa, and the subsessile foliage of 

 Echiuin vulgar e and Beta, will illustrate this. 



Anemone furnishes three conditions. In A. nemorosa the invo- 

 lucre is formed by three complete petiolate leaves ; in ^. Pulsatilla 



* Vol. ii, pi. 21, figs. 4-6. t p. 271. 



X Payer, 'Elements de Botanique,' p. 90, tig. 144. 



