Weels and Trellises. 85 



tudinal section of a single nectariferous epiblasteme). 

 Strong and flying insects that approach the flower from 

 above, and, in sucking the nectar, strike the stigma and 

 the anthers in due succession, can push their proboscis 

 between the bars of the trellis that covers in the nectar- 

 pit; while smaller insects, that try to creep in from 

 below and from the side, and so would not come into 

 contact with stigma and anthers, are excluded from the 

 nectar by means of the trelHs. In Malvaceae the 

 nectar is secreted in smaU hollows placed at the basal 

 commissures of the united petals; and each of these 

 little hollows is guarded by a "weel" of radiaUy- 

 set trichomes (Plate III. fig. 105, Malva rotundifolia. 

 Transverse section of corolla, close to the bottom of the 

 flower). 



Such "weels'' and trellises are also often to be 

 found on parts of the androecium. For instance, in 

 Haphphyllum patavinum (Plate III. fig. 109, longitu- 

 dinal section of flower), the lower portion of the fila- 

 ments is furnished with trichomes which point inwards, 

 and form a trellis- work over the nectariferous disk that 

 supports the ovaries. A similar formation is also to 

 be seen in Physalis atrvpUcifolia. In this instance the 

 trichomes are, it is true, very short ; but this is com- 

 pensated by a knobby thickening of the base of the 

 filaments. Often again the stiff filaments stand in a 

 circle round the nectary, like the staves of a cask, and 

 have their lateral margins beset with trichomes that 



