Naturalisation in Extra-Tropical Countries. 537 



by which name also T. medium is sometimes designated. Highly 

 recommendable for permanent pastures, particularly in cool humid 

 climes, as it continues to grow year after year, and produces a large 

 amount of herbage [Dr. Curl]. It prefers rich ground and particu- 

 larly soil, which is not devoid of potash and lime ; gypsum-dressings 

 are recommendable for the fields. Perishes in stagnant moisture. It 

 enters into the rotation-system of crops very advantageously. The 

 annual average yield of hay is 40 cwt. from an acre by cutting 

 twice, but sometimes twice as much is obtained. The nectar of the 

 flowers is much sucked by bumble-bees ; this tends to facilitate the 

 production of seeds. Clovers and Lucerne are subject to be attacked 

 by some kinds of parasitic plants, namely, species of Cuscuta and 

 Orobanche, from which fields must be held free by using well-sifted 

 seeds only, or by ploughing in before the parasites come into fruit. 

 If badly infested, land should be kept fallow for awhile and be 

 periodically stirred ; any Dodder-seeds, left in the soil, will germinate 

 when brought to the surface, but their seedlings will die off in the 

 absence of the foster-plant. 



Trifolium reflexum, Linn6. 



The Pennsylvanian or Buffalo-Clover. Eastern North-America. 

 Annual or biennial ; flower-heads larger than those of the red clover ; 

 likes alluvial flats. 



Trifolium repens, Bivin.* 



The ordinary White Clover, called also Dutch Clover and Sham- 

 rock-Clover ; the emblem-plant of Ireland. Europe, North- Africa, 

 Northern and Middle Asia, sub -arctic America, ascending the 

 European Alps to 8,000 feet. In Norway indigenous to lat. 70 57'. 

 Perennial. Most valuable as a fodder-plant on grazing land. It has 

 a predilection for moist soil, but also springs again from dry spots 

 after rain. It likes soil containing potash and lime, prospers on 

 poorer ground than red clover, is more nourishing and better digested, 

 and- less exhaustive to the soil. Dressing with gypsum vastly 

 enhances the value and productiveness of any clover-field. Fresh 

 wood-ashes are for the same purpose recommendable [Dr. Stebler] . 

 Among valuable clovers the one which gets naturalised more easily 

 than any other in appropriate localities. Important as a bee-plant. 



Trifolium resupinatum, Linn6. 



The annual Strawberry-Clover. From South-Europe and North- 

 Africa to Persia ; also in the Canary-Islands and Azores. Admitted 

 here, though annual, as this clover is cultivated with predilection in 

 Upper India, also in Afghanistan ; it is quite a useful pasture-plant, 

 though small, closely cropped by herds and flocks, and then continuous 

 in growth ; easily naturalised. Headlets of flowers conspicuously 

 produced. Mr. Stuart Reid observes that it will live through drought 

 and floods. 



