646 



BOTANY OF THE LIVING PLANT 



Gynoeclum, carpels 2, syncarpous, superior, antero-posterior ; style elon- 

 gated ; stigma two-lipped, lying between the pairs of anthers, with lobes 

 widely divergent, the anterior lobe directed downwards. The ovary 4-partite, 

 with one anatropous ovule in each. It is really bilocular, with two ovules 

 in each loculus ; but it becomes " falsely " quadrilocular by intrusion of a 

 septum between each pair of ovules. Nectaries are found at the anterior 

 base of the ovary. The nectar accumulates in the narrow lower part of the 

 corolla-tube, protected by a fringe of hairs which grow inwards from the tube 

 of the corolla just above the ovary. 



Fig. 496. 



Lamium album. I. flower seen laterally. II. same in frontal view. III. dissection 

 showing ovary and style, and the base of the corolla-tube, with insertion of stamens 

 and fringe of hairs. IV. ovary as seen from above. V. floral diagram. 



Fruit, four dry nutlets, two being derived from each carpel. They remain 

 till shed, enclosed by the persistent calyx. 



Pollination is by bees, which alight on the lower lip of the corolla and insert 

 Jie proboscis into the tube. The bee's body fills the space between the upper 

 and lower lips, so that its back presses against the stamens and stigma. The 

 anterior lobe of the stigma projects further downwards than the stamens, so 

 that it first touches the back of the bee, receiving pollen if she has brought any 

 from another flower. She then receives pollen from the anthers which open 

 downwards. The flower is homogamous, that is, the stigma is receptive at the 

 time when the pollen is shed. Self-pollination is therefore possible, but there 

 is a high probability of cross -pollination. 



(41) The Dead Nettle is highly specialised, and deposits the pollen on a 

 limited area of the insect's body ; but a still higher degree of specialisation is 

 seen in Salvia pratensis, or other species. The plan of the flower is the same as 



