248 ALPINES AND BOG-PLANTS 



in the rock-work. Lastraea thelypteris is a larger, rather 

 uninteresting fern for the bog ; Lastraea oreopteris is stiJBf 

 and stark in its upright growth, from open, heathy banks 

 on the fells. Lastraea rigida, if one could get it, 

 has the attraction of extreme rarity, and still lurks 

 undiscovered among the common Lady - ferns on the 

 upper slopes of Ingleborough, whence it was first 

 recorded. On the same slope occurs the Parsley Fern — a 

 mere caricature of itself as it luxuriates on the slates and 

 primary formations of the Welsh mountains. But 

 though I have seen AUosorus crispus making stout bushes 

 by the stream-sides that flow down to Llyn Idwal, I have 

 had so uniformly disheartening an experience with this 

 fern on my limy soil, that I will not give it any recom- 

 mendation for the bog. 



Finally comes the one grass that is really of prime 

 value for the rock-garden and the bog (not mentioning 

 Festuca varia, beautiful neat cushion of finest emerald 

 fur, even in midwinter). Poa alpina is indistinguishable 

 in growth from the tufts of any common grass that one 

 rends up as a weed. But in its viviparous form the plant 

 produces rich heavy masses of living baby plants, the 

 whole blossom-head being a great tassel of plumy emerald 

 touched with crimson. Beneath their load the frail stems 

 bend earthward, and there in due time deposit their load, 

 each sprouting bulblet producing a young plant. Poa 

 alpina vivipara is quite common in the Alps, and occurs 

 very rarely in the Highlands and in western Ireland — 

 notably on one mountain overhanging the sea. In 

 cultivation it is perfectly easy and robust, thriving in any 

 rich, damp loam. Its only drawback is its very close 

 resemblance, while out of flower, to its common cousins, 

 which often causes Poa alpina to be weeded up, while the 

 real weed next door is left untouched. 



In dry clefts of every wall in the Ligurian vineyards 



