270 



McDonald : T/ic jDoo\s' A/crc/zn'. 



odour quite distinct from that of the bruised fohage,* and to* 

 the writer and several friends is suggestive of the rather nasty 

 odour given off by the flowers of the Privet [Ligmtviim vul^are). 

 This odour may be the chief means of attracting the midges, 

 etc. Probably both wind and insect polhnation occurs. The 

 clustering of the flowers is advantageous to both kinds of pol- 

 lination, though more information on this point would be 

 welcome. Considering the number of pistillate flowers, the 

 percentage of ripe seeds one can gather in a season is not a great 

 one. Possibty, in spite of efficient pollination the cold weather 

 prevailing during the flowering season is unfavourable to fer- ■ 

 tilization. I cannot bring myself to look upon the rather low 

 percentage as due to vegetative multiplication, as has been 

 suggested, for wherever both sexes grow near together seedlings 

 may be found almost every year ; at least, that is my experience. 



After the flowering period is over the peduncle of the 

 staminate spike usually falls away, leaving a small scar where it 

 left the stem The stem itself continues to grow till late 

 summer in both staminate and pistillate plants, so that in the 

 latter the developing fruits are partly hidden. Some of the 

 fruits ripen towards the end of June. The lobes then split 

 apart, technically the fruit is a schizocarp dehiscing septici- 

 dally into two mericarps or cocci, and each lobe (mericarp, 

 carpel, or coccus), further dehisces elastically in a loculicidal 

 manner, ejecting the seed with great force (Fig. 17). Many of 

 the seeds of the order Euphorbiacese have a small fleshy appen- 

 dage near the micropyle termed the caruncle. When the 

 seeds of Dog's Mercury are examined, it will be found that 

 traces of this caruncle are present, though it does not become, 

 fleshy. This character is a little more pronounced in the 

 Annual Mercury [Mercurialis annua). A few comparisons 

 with the latter may not be out of place. In this mercury the 

 cotyledons are usually epigeal, and rise some distance above 

 the soil. The cotyledonar}^ buds, as do other buds from the 

 foliage leaves, grow into branches. As we have seen, buds^ 

 are not formed above ground in the Dog's Mercury, or rather 

 they do not develop. The leaves of the Annual Mercury are 

 more ovate, bright green, and smooth. The flowers are similar 



* After gathering a few specimens with flowers open, the leaves were 

 bent downwards and worsted wound gently round to keep them in that 

 position, the flowers being then clustered above the foliage. After allow- 

 ing a little time for the smell of bruising to fade away, the distinct odour 

 of the flowers was perceived. 



Naturalist, 



