NATURAL HISTORY SOCIETY OF GLASGOW. 223 



prove its character. The same thing may be said of Turnips and 

 Carrots, which grow wild on our shores, and attain their highest 

 perfection in light, sandy soils. The Cabbage presents an interest- 

 ing case. The wild equivalent is a shore plant, but under cultivation 

 the leaves, rather than the root-stock, tend to become succulent. 

 In the Kohl-rabi, however, there is a fleshy bulb (Sprengel). 

 The Jerusalem Artichoke {Helianthus tuberosus) grows to 

 greatest perfection where there is a dry, hot summer. 

 Plants of our native flora possessing tuberous structures too, 

 usually grow in dry situations — e.g., Ranunculus Jicaria — whose 

 fasciculate roots, partly fibrous, partly tuberous, are adventitious, 

 the plant being perennial. It is instructive to compare the roots 

 of this plant with those of its near ally the Marsh Marigold (Caltha 

 palustris), which, growing in streams, has no tubers. An enlarged 

 or succulent rhizome is frequently found in plants growing in dry 

 situations, thus Spiraea Jilipendula, with a short root-stock and 

 fibres interruptedly tuberous, according to Hooker, grows in dry 

 pastures, while S. ulmaria, frequenting meadows and watersides, 

 is not so provided. In England, Bryony possesses tubers, and 

 grows in such situations ; the rootstock of various species of 

 Plantago, growing on sandy and gravelly soils {P. coro^nojms), 

 Corydalis bulbosa, together with some members of the orders 

 Convolvulaceae, Compositae, Cruciferae, Leguminoseae, and 

 Umbelliferae (Daucus), exhibit a like tendency. There are, 

 however, marked exceptions — e.g., the Cow Parsnip, with 

 many Orchids, Lilies, Iridaceae {Iris, Gladiolus, Crocus), and 

 Amaryllklaceae [Galantines), are found in moist, shady situa- 

 tions While, therefore, there can be little doubt in the case 

 of tap-roots and tubers that they are directly related to a light 

 soil and arid climate, it is by no means so clear in the case of such 

 bulbs as those of the Lily, Onion, Hyacinth, Crocus, and rhizomes 

 like that of Solomon's Seal, that they are directly related to with- 

 standing droughts. It is not impossible that some of these bulb- 

 bearing plants may be at an advantage as regards capability of 

 withstanding cold (protected under ground under snow), as opposed 

 to annuals grown from seed germination. As a matter of fact many 

 of our earliest flowers are of this class, Snowdrop, Lily of the 

 Valley, ISTarcissus, and Crocus. This much, however, appears, 

 that such plants are most characteristic of prairies and steppes — 

 tracts subject at one period of the year to floods, and to another 



