Note on Aponogeion distach^on 19 



the water being enabled to do so by means of an oily testa. After 

 floating for eight days the testa splits and the " seed " sinks and 

 germinates in the soil below. 



Within four days of sinking a long slender structure appears 

 and grows towards the surface of the water and a few days 

 later two radicles, one at the apex of the " seed ** and one next 

 to the plumule appear. They grow into the soil and fix the 

 young plant. On reaching the surface of the water the apex of 

 the structure which first appears from the '* seed '* bends at right 

 angles, becomes flattened and forms the lamina of the leaf. 



In connection with the germination of Aponogeton distach\fon 

 Dr. Marloth (Trans. S. Afr. Philos. Soc. vol. 8. p. LXXX) 

 states that *' the seed germinates while floating on the surface 

 and gradually forms the bulb. When this becomes heavy enough 

 it sinks, and the plant fixes itself permanently.*' This does not 

 agree with my observations made on plants grown at Pretoria as 

 germination took place below water, except in one instance when 

 the seed did not completely escape from the oily testa and in this 

 case germination commenced on the surface. 



Explanation of Plate. 



Fig. A. — Mature plant with leaves only. 



Fig. B. — Young inflorescence before opening. 



Fig. C. — Inflorescence with surrounding sheath beginning to 

 split. 



Fig. D. — Expanded inflorescence. 



Fig. E. — Carpel with pericarp. 



Fig. F.— Seed. 



Fig. G. — Seed escaping from testa. 



Fig. H.I.J. — Stages in germination of seed. 



Fig, K. — Mature root system. 



