THE ANGIOSPERMAE 



120: 



question whether terminal carpels do exist. We have already seen (p. 1 120) 

 that in the most conspicuous case of apparently terminal single carpels, 

 i.e., in the Leguminosae, the evidence of residual vascular bundles indicates 

 that the carpel occupies a lateral position, which has become apparently 

 terminal by the abortion of the receptacle apex, coupled with the dis- 

 appearance of the other members of the original carpellary whorl. The 

 latter, moreover, still exists in the small genus Affnnsea (Fig. 1175) in the 

 Mimosaceae, which has a whorl of three. Although it is inadvisable to be 



Fig. 1 175. — Affonsea juglcuidifolia 

 (Mimosaceae). Longitudinal 

 section of flower showing whorl 

 of carpels. (After Baillon.) 



Fig. 1 176. — Punica granatuui , Pome- 

 granate. Vertical section of 

 flower showing two superposed 

 whorls of carpel loculi in the 

 inferior ovar>-. {After Le Maout 

 and Decaisne.) 



dogmatic, it may be concluded that the terminal position of a carpel, like the 

 terminal position of a stamen in a few male flowers (p. 1180), has been 

 arrived at secondarily, in most cases, by abortion and a shift of position due 

 to the greater growth rate of the carpel compared with the receptacle apex. 

 There is very rarely more than a single whorl of carpels, even when they 

 are free and the number of other parts in the flower is large. A super- 

 numerary upper whorl of small sterile carpels occurs as an abnormality m 

 the Orange, giving rise to the variety called the Navel Orange, where they 

 form a small, imperfect group at the apex of the ripe fruit. Two whorls of 

 carpels appear, however, to be normally formed, all being fertile, in some 

 of the lower Monocotyledons, e.g., Butomiis, Alisma, and Tn'glochin, in 

 which the number of carpels is double, or more than double {Alisma), 

 the number of stamens in a whorl. The Pomegranate, Piimca granatiim 

 (Fig. 1 176), presents a unique case, for there are here, in a syncarpous and 



