POLYPETAL.E 63 



the perianth is perigynous or situated around the 

 ovary, in which case the parts appear superior, 

 whilst the ovary is still superior, or the stamens are 

 epigynous, or upon the ovary, and the ovary is thus 

 inferior. Exceptions occur, however, in each case. 



In the Polypetalas the flowers have both calyx 

 and corolla, and are, therefore, dichlamydeous. The 

 petals are free. This last feature, however, is present 

 in some Monopetalas, as in Ericaceae, in Pyrola and 

 Monotropa, and in Plumbaginacese. In Polypetalae, 

 also, the calyx or corolla is sometimes absent. In 

 some Ranunculaceae, in Meadow Rue, Wood 

 Anemone and Marsh Marigold there are no petals, 

 the sepals being petaloid. There are also in Cruci- 

 ferae exceptions, including plants with no calyx 

 or corolla, in some species of Cardaminey Wart 

 Cress, and Pepperwort, and some species of Violet 

 are sometimes apetalous. In Caryophyllaceae 

 petals may be absent in Arenaria, Cherleriaf and 

 Sagina, 



In Rosaceae there are no petals in Alchemilla or in 

 Poteriuniy nor amongst Saxifrages in Chrysospleniiim, 

 In Halorageae the flowers are apetalous, and amongst 

 Lythraceae in Peplis, amongst Onagraceae in 

 Ludwigia, 



THALAMIFLORiE (FlOV^ERS ON A RECEPTACLE OR 



Disk). 

 The petals are usually distinct and separate in this 

 group, or absent. The petals are in 1-2 or an 



