EXAMINATION OF FLOWERS. 105 



is situated below the ovarium, or germen, or includes this 

 part within its whorl, then the calyx, or corolla, is inferior 

 Ex. Lily, Pink. 



When the calyx, or corolla, is placed on the ovarium, and 

 does not include it, then it is superior. Ex. Apple, Hydran- 

 gea. 



When the ovarium is partly above and partly below tho 

 corolla, or calyx, then these parts are half superior, or half 

 inferior. 



6. In the examination of flowers, containing many sta- 

 mens, it is required to ascertain whether these parts are sit- 

 uated on the calyx, or not. If there are many stamens, that 

 is, more than twenty, inserted on the calyx, the plant falls un- 

 der the class ICOSANDRIA ; but if these parts are fixed under 

 the ovarium, and on the part sometimes called the receptacle, 

 it comes within the class POLYANDRIA. 



7. If the flower has four stamens, two of which are longer 

 than the others, it belongs to the class DIDYNAMIA. Plants 

 of this description form the natural order called the Labiates, 

 or Mint tribe. The flowers often grow in whorls, and are 

 readily known by their labiate, gaping, corollas. See Fig. 

 113. 



8. If the flower has six stamens, two of which are dis- 

 tinctly shorter than the others, it falls within the class TET- 

 RADYNAMIA. Plants of this description, form the natural or- 

 der Crucifera, or cruciform plants, so called, because their 

 petals, being only four in number, are so placed as to make 

 the figure of the cross. Cabbage and Mustard, are exam- 

 ples. See Fig. 117. 



9. It is generally easy to decide whether the filaments 

 are separate at the base, or united. In the first ten classes, 

 these parts are distinct throughout. If they are united to- 

 gether in any part of their length, or at the base, then the 

 plant falls under some class not yet mentioned. If the union 

 is in one parcel, the flower is MONADELPHOUS. Ex. Gera- 

 nium, Mallows. If the stamens have their filaments collected 

 into two parcels, however unequal in number, the flower is 

 DIADELPHOUS. In the Pea, for example, there are ten sta- 

 mens, nine of which are in one set, and one in the other. 



In a few instances the filaments are united into more than 

 two parcels, in which case the plant falls within the class 

 POLYDELPHIA. Ex. Hypericum. 



