Naturalisation in Extra-Tropical Countries. 431 



Prunus tomentosa, Thunberg. 



Northern China. A very hardy species with cherry-like edible 

 fruits. Some temporary screening during severe weather at the 

 flowering time of orchard-trees would obviate much diminishment in 

 the fruit crop ; such shelter might be of framed calico or other cheap 

 movable contrivances available again in other seasons. 



Prunus Virginiana, 



The Choke Cherry-tree of the Eastern United States. In a mild 

 clime and fertile soil this tree attains a height of about 100 feet and 

 a stem-circumference of 16 feet. Endures the winters of Norway to 

 lat. 67 56' [Schuebeler]. The wood is compact, fine-grained, and 

 not liable to warp when perfectly seasoned, of a dull light-red tint, 

 deepening with age. The fruit finally loses its acerbity. The bark 

 used in medicine. 



Psamma litoralis, Beauvois.* (P. arenaria, Roemer and Schultes ; P. 

 arundinacea, Host ; Calamagrostis arenaria, Roth ; Arundo arenaria, 



The Morram, Marrum, Marrem or British Bent-grass. Sand- 

 coasts of Europe, North- Africa, and Eastern North America. One 

 of the most important of reedy grasses with long descending roots, 

 to bind moving drift-sands on the sea-shore, for the consolidation of 

 which this tall grass and Elymus arenarius are chiefly employed in 

 Europe. It delights in the worst of sand drift, and for its full 

 development gradual accumulation of fresh sands around it becomes 

 necessary [Wessely] : hence it never gets suffocated. It has great 

 tenacity of life ; even when long dislodged and looking withered or 

 dead, it may sprout again from the root. Not readily igniting. 

 Easily started from portions of roots for new growth, but also often 

 sown. Can also be grown in sandy saline inland localities. A 

 wooden palisade should be erected near high-water mark, to promote 

 the formation of an artificial dune ; under such shelter the Marrem- 

 seeds are sown and covered with brushwood, to prevent the seed 

 thus sown from moving. (" Indian Forester " xni., 450.) In South' 

 Africa, any street refuse is used to cover sand on which plants for 

 arresting drift are to be sown. Mr. S. Avery found that cattle, one 

 head per acre can be kept in Marram-grass plantations in the frostless 

 regions of Port Fairy during the cool moist season, when the growth 

 of the plants is vigorous, and that the animals thrive well on this 

 pasturage. In countries with severe winters this procedure could not 

 likely be carried out, as it would too much enfeeble the plants. The 

 plant will by gradual up-growth finally form stems and roots, sanded 

 in to a depth of fully 100 feet. Psamma Baltica (R. & S.), from the 

 Baltic and North-Sea, serves the same purpose. Both can also be 

 used to some extent in the manner of Sparta for paper material, for 

 tying and for mats. Like Elymus arenarius, they are not generally 

 allowed to be touched by grazing animals. P. arenaria collects the 



