313 



both from Greenland and Iceland. Regarding M. alternifiorum 

 from one of the localities Kingua Neriak, Greenland, N. Hartz 

 who found it reports on the label, that it grew "on the bottom 

 of a lake." In Denmark I have observed root-formation in the 

 upper stalk part even when the shoot occurs on the surface 

 of the water, in M. spicatum and M. verticillatum^ at a depth 

 of 2 — 3 m in Furesø and on a moor, in a trench of slight 

 depth, in August ; in the last case roots even sprang from the 

 bracts of the flowers ^ In running water at Fiskebaek on Furesø 

 both Myriophijllum and Batrachium had a similar root-formaton, 

 here perhaps deeper in the water. As known, the broken-off 

 shoots of a number of water-plants have the power to develop 

 roots both in the lower and upper parts. Sernander (1901 p. 

 100) has remarked specially regarding M. spicatum that it is 

 found in the autumn "with long roots high up on the shoot". 



The branching is generally as Irmisch (1859 p. 354) notes 

 for M. verticillatum , shoot-formation from only one of the 

 leaves in a whorl; in M. alternißorum from Friedrichsthal, Green- 

 land, and from a lake at Kobbermine Island at Julianehaab as also 

 from Breidalur, Iceland, 2 — 4 shoots spring from one leaf-whorl. 



The material does not show how the winter is passed ; it 

 contains no winter-buds. But at the base of the air-shoot 

 in a number of M. spicatum there are leaves which differ 

 from the ordinary by having larger lobes and a somewhat 

 similar appearance to the leaves in hibernacula of Danish M. 

 verticillatum. The lateral shoots from the axils of such leaves 

 bear ordinary, finely divided leaves. 



As the three Myriophyllum species are so difficult to 



distinguish from one another in the vegetative condition, there 



might be a possibility in statements regarding the winter-buds 



in M. a. and M. spic. of confusion with M. verticillatum . 



' The formation of roots from the nodi of the upper, horizontal part of 

 M. spicatum in running, ca. I m deep water is mentioned by 0. Rosen- 

 berg: Oni växternas utbildning i rinnande vatten. Svensic hot. tidsskrift. 

 Band 1. 1!I07. Stociiholm. 



