COROLLA. 377 



requires modification. In the case of polypetalous, or 

 rather dialypetalous flowers, the petals may be very 

 largely increased by multipUcation, as in roses, ane- 

 mones, pinks, &c. In the last-named genus the number 

 is often so much increased that the calyx splits from 

 the tension exercised on it by the increasing mass 

 within. This multiplication may happen without any 

 metamorphy or substitution of petals for stamens, 

 though, in the majority of cases, it is associated with 

 such a change. It is curious to observe in some 

 of these flowers that the total number of parts is 

 not greatly increased ; thus, in some of the double- 

 flowered Legicminosce, such as Ulex eurcypwns and Lotus 

 coniiculatuSj the petals are repeated once or twice, the 

 stamens are petalodic, but reduced in number, while 

 the carpels are usually entirely wanting. Thus, owing 

 to the diminished number of parts in the inner 

 whorls of the flower, these very double-looking blooms 

 do not contain any greatly increased number of 

 parts. ^ 



Flowers that, under ordinary circumstances, are 

 ganiopetalous, become, in some instances, multiplied 

 by the formation of additional segments, just as in the 

 case of polypetalous corollas ; but in these cases the 

 corollas become polypetalous, their petals do not co- 

 here one with another. Among double flowers of this 

 character may be mentioned Ca7npanula rotundifoUa, 

 Gardenia sp., Nerium Oleander, Serissa sp.. Arbutus 

 Unedo, &c. The change is associated with petalody of 

 the stamens and pistils. 



A more frequent change among the monopetalous 

 orders is the duplication or triplication of the corolla, 

 in consequence of which there appear to be a series of 

 corollas enclosed one within the other, the lobes of 

 jvhich generally alteraate with one another, but which 

 sometimes are superposed. This happens occasionally 

 in the primrose {Primula acaulis)^ and constitutes the 

 variety called by the gardeners " hose in hose." 



C. Morren, ' Bull. Acad. Belg.,' xix, part ii, p. 17. 



