ERYNGIUM. 
be disgraced by the ensuing dingy heads of blossom enclosed in a cup 
of pointed bracts like some Protea or an Artichoke gone mad)—it is 
important for the rock-garden to know which species will best suit 
its style, and, more important still in one case, which is which. For 
beautiful H. amethystinum is often sent out under the name of the 
much more beautiful and much rarer 7. alpinum. But the two are 
very easily known apart. Look down from above upon the 
hard sugar-loaf of blossom enclosed in its wide-spreading frill of steely 
blue: if that cup be handsomely but thinly starry, with long spiny 
bracts rather broad and stiff and solid, and owning a toothing here and 
there, then the species is #. amethystinum. But now what a change. 
Look down upon the next: here the frill is double, treble, quadruple, 
and each bract is toothed again and again into long thorny-looking 
spines of its own, until the whole effect is that of a blue lacy collar of 
richness unparalleled. This is the only, the unsurpassable FZ. alpinum, 
a plant of the mid-alpine limestones, scattered locally here and there 
along the mountain chains, nowhere in any great quantity, though 
common enough in the small limited stations where it occurs. But in 
nature, accordingly, it is a prize of such preciousness that it should 
neither be dug nor picked—even if its root did not forbid the one crime, 
and the hope of seed dehort from the other. It is indeed a superb and 
uncanny splendour of some foot or 18 inches high, blooming through 
the later fuliness of summer, and, like all its kind, perfectly happy in 
the rock-garden in any very deep loam. No other, following, can 
compete with this, except its peer, HZ. gigantewm, of nearly a yard 
high, from the Caucasus, with much the same frill, but here of an 
ivory-white so ghostly-clear that the plant is called Elves’ Bones. For 
the rock-garden, too, is fitted rare and lovely H. Spinalba from the 
Southern European ranges, about 18 inches high, firmly spinous, with 
stems and irill of a silvery pale grey-blue fading into white. But for 
places of choice, even in the very foreground of the rock-work, there 
are two species of front rank to match. Of these EH. prostraium, in 
our gardens, forms a quite small central rosette of thin oblong green 
leaves, sparingly toothed and wholly unarmed, from which lie out upon 
the earth in a star all round short prostrate stems of 3 or 4 inches, 
with flowers and frills of a beautiful blue. This is sometimes treated 
with tenderness, and felt to be impermanent, if not a biennial, even when 
grown in good rich ground on sunny exposures. In point of fact, this 
is a bog plant from Texas, and in damp places should make a running 
carpet, rooting as it goes, along all its ground-hugging branches. Quite 
different from this is the last Eryngium with which it is at present 
necessary for the rock-garden to concern itself (though there are many 
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