AfJD INSECT AID. 229 



In this manner cross-fertilisation is secured. I have often noticed 

 a large number of small insects, especially flies, safely imprisoned 

 in the Arum before the hairs have shrivelled up. 



Proterandrous plants, or those in which the anthers mature 

 before the stigmas, are much more numerous. As examples 

 amongst the wild flowers which are to be found in this locality,* I 

 must mention Wild Thyme {Thymus serpyHum), Rose Bay, Willow 

 Herb, Epilohium augustifoliiim, Blue Meadow Crane's ^\Vi{Geranium 

 prate nse), Mountain Crane's Bill, {G.pyrenakum), with many of the 

 Uinbelliferce and most of the Composihv. Sir John Lubbock states 

 that most of the British wild flowers which contain both stamens 

 and pistils are more or less proterandrous. These are almost 

 dependent upon the visits of insects for fertilisation. Amongst 

 foreign plants now common in conservatories, Clerodendron 

 Thompsonii {^\. XXIV., Fig. i), a verbenaceous African climber, 

 is a good example of a proterandrous plant. Its crimson corolla 

 and bright white calyx in combination are very conspicuous and 

 serve to attract insects. The long iiliform filaments and style, 

 upwardly enrolled in the bud, straighten and project when the 

 corolla opens, the stamens remain straight, but the style proceeds 

 to curve downward and backward, as shown at a ; the anthers are 

 represented discharging the pollen ; the stigmas are immature and 

 closed ; b represents the flower on the second day, and anthers 

 effete, and the filaments recurved and rolled up spirally ; while the 

 style has taken the place of the filaments^ and the two stigmas, 

 now separated and receptive, are in the very position occupied by 

 the anthers the previous day. The entrance by which the proboscis 

 of a butterfly may reach the nectar at the bottom is at the upper 

 side of the orifice. It is impossible for the flower to self-fertilise. 

 A good sized insect flying from flower to flower, and plant to plant, 

 must carry pollen from one to the stigma of the other. 



I cannot help calling attention to the mode in which 

 cross-fertilisation is secured in the Blue Meadow Crane's Bill 

 {Geranium pratensc), Fig. 3, for several reasons. This beautiful 

 Crane's BiU, with its lovely blue corolla and elegant leaves, must be 

 well-known to all who stroll in the meadows adjoining the Avon 



* Bath. 



