The President's Address. By Lord Avebury. 143 



We have only one British, the Black Bryony, Tamus com- 

 munis. It does not extend to Scotland or Ireland, and is, indeed, 

 confined to the South of England. It is widely distributed over 

 Europe, North Africa, and temperate Asia. 



The flowers are small, yellowish-green, in slender racemes. The 

 berry is oblong, indehiscent, bright red at maturity, and contains 

 about five seeds. 



The seeds are large, globular, minutely and finely netted, the 

 meshes being arranged, more or less regularly, in longitudinal lines. 

 They are slightly flattened at each end, like an orange. The testa 

 is membranous, and light reddish-brown. 



The fruit, though not attractive to us, is eaten by birds. The 

 seeds, being very hard, no doubt escape digestion, and are in all 

 probability as a rule rejected. 



The cotyledon has lost almost all trace of its leafy character, 

 and seems to absorb nourishment from the seed. 



In the first year only one leaf develops. It is situated almost, 

 or perhaps directly opposite to the cotyledon, so that it might 

 easily be taken for a second cotyledon. 



Miss Sargant * has adopted the suggestion originally made by 

 Agardh, that the Monocotyledons are derived from Dicotyledonous 

 ancestors, and their single cotyledon is derived from the fusion of 

 the two cotyledons of their ancestral Dicotyledon. Some of the 

 Kanunculacere show, no doubt, a tendency in this direction, as, for 

 instance, species of Ranunculus, Trollius, Delphinium, Anemone, 

 Aconitu/n, Eranthis, etc. More or less similar cases occur in other 

 orders, as, for instance, in Corydalis. Miss Sargant also points out 

 that some Monocotyledonous cotyledons seem to show traces of a 

 double origin : thus, that of Chamtvrops humilis has a bifid apex, 

 and that of C. Fortunei is even more completely bilobed. I doubt, 

 however, whether these cases have in reality any bearing on the 

 problem. It seems more probable f that the advantage is in 

 giving greater strength. 



On the other hand, Mr. Hill % considers that the Monocoty- 

 ledonous habit may have been acquired by the adaptation of the 

 two cotyledons of the ancestral Dicotyledons to different functions 

 — one acting as a suctorial organ, the other developing into a typical 

 aerial leaf. 



Amaryllide^:.— The ovary is inferior and 3-celled. The fruit 

 is a capsule, opening in three valves, loculicidally, or fleshy and 

 indehiscent. The seeds are few, numerous, or reduced to one only. 

 The order comprises about sixty genera and 650 species, mostly 

 perennial and bulbous. The species grow mostly in tropical and 

 warm regions. We have three genera and four species, two of 



* Sargant, Ann. of Bot., xvii. 



t Aveburv, " On Seedlings," pp. 90-97. 



% Ann. of Bot., xx. (1906). 



