SUPPRESSION OR ABORTION OF PARTS. 255 



mainly to the corolla, tlie lower petal of which is prolonged back- 

 ward into a sac or spur. The Larkspur and Monkshood (Fig. 398- 

 402) ai-e irregular both in the calyx and the corolla, not only by a 

 diversity in the size and shape of homologous parts, but also by the 

 suppression of some of them. We may therefore consider them 

 under the next head. 



473. Of irregular monopetalous flowers the most common form is 

 the hilahiate or two-lipped, as in the corolla of the Sage, Snap- 

 dragon, and most of the large families to which they belong (Fig. 

 460) : this, like the calyx of the Lupine, described above, arises 

 from the unequal union of the parts. The same is the case with 

 the two-lipped corolla of the "Woodbine and other Honeysuckles, 

 only here, instead of two lobes or petids fomiing the upper lip and 

 three the lowei-, four petals enter into the composition of the upper 

 lip, leaving only one for the lower (Fig. 861). The Trumpet 

 Honeysuckle returns nearly to regularity again, the whole five 

 petals being coalescent into a tube to near the top, leaving an al- 

 most equally five-lobed border. The corollas of Germander (Fig. 

 996) and of Lobelia (Fig. 902) are further irregular by a want of 

 union on the upper side of the blossom : and the ligulate or open 

 and strap-shaped corolla of Coreopsis (Fig. 325, c) and other Com- 

 posita3 evidently answers to such a regular monopetalous corolla as 

 a, split down on one side and outspread. 



474. Suppression or Abortion, that is, the complete or the partial 

 obhteration of some member, is a common cause of irregularity. 

 The term suppression is used when parts which belong to the plan 

 of the blossom do not actually appear in it. The term abortion is 

 applied not only to such disappearance, but to partial obliteration, 

 as where a stamen is reduced to a naked filament, or to a mere rudi- 

 ment or vestige, answering to a stamen and occupying the place 

 of one, but incapable of performing its office. Such obliteration, 

 whether partial or complete, may affect either a whole circle of 

 organs or merely some of its membei"s. The former interferes with 

 the completeness of a flower, and may obscure the normal order of 

 its parts. The latter directly interferes with the symmetry of the 

 blossom, and may be first considered. 



475. Suppression of some Parts of a Circle of Organs. The Larkspur 

 and Aconite or Monkshood furnish good examples of flowei*s which 

 are both irregular and symmetrical. The calyx of the Larkspur 

 (Fig. 398, 399) is irregular by reason of the dissimilarity of the five 



