72 President's Address. 



at that season most interesting and beautiful objects. This family is 

 divided into numerous sections botanically, but for our purpose it 

 may be arranged into two divisions, viz., the mossy section, of which 

 our native S. hypnoides is tbe type ; and the silvery one, of which 

 the alpine S. Aizoon may be taken as the most familiar example. 

 The mossy section is a very large one, and I have seen collections 

 numbering more than fifty species, varying even more in the different 

 tints of green during the winter than the flowers of the different 

 species do in summer. The silvery section also show themselves well 

 during the winter, some large and bold, with strap-shaped leaves, 

 margined with distinct white dots, such as S. pyramidalis, Cotyledon, 

 and longifolia; others forming round swelling masses of silvery 

 rosettes, such as .S^. ccesia, Rochelliana, and Bursenana. They are all 

 easily grown, and onl}' suffer during the spring in dry cold winds or 

 during a great drought in summer, when a little water soon revives 

 them. A friend of mine raised a very beautiful yellow-flowered 

 variety of S. Burseriawi from seed, and it is quite as free a flowerer 

 as the ordinary white flowered form ; he had also a number of crosses 

 between *S'. Burseviana and RocheUiana, most of them having the leaf 

 of Burseriana, with a numerous branching head of flower, as in 

 Rochelliana. ]\Iany of the varieties of the hypnoides section form 

 nice plants for hanging over bare stones, or as edgings to the beds. 

 A very pretty variety called S. Macnahiana raised from seed of 

 8. pyramidcdis by the late ^Ir M'Xab, with richly spotted flowers, 

 is grown largely in the Botanic Garden, Edinburgh. 



Erodium Richard/', a dwarf geranium-looking plant, ncA^er more 

 than about 2 inches high, is well worth growing ; it, however, re- 

 quires to be well looked after in winter, and it will always be well 

 to have a duplicate in the cold frame, in case of the plant being 

 lost outside. Sedum is a large group, and many of them are very 

 useful rock plants. The three finest I have are S. JEtversii, a rich 

 purple-flowered dwarf variety, S. cyaneum, and S. Beyrichiamim. 

 This last requires to be carefully looked after, as it is apt to flower 

 itself to death. A plant or two should be kept, with the flower 

 stems cut off as they rise during summer ; if this is done, the plant is 

 quite hardy, and will stand any winter, but it generally dies after 

 floAvering profu.sely, which it usually does if the flower stem-s are not 

 nipped off. S. cyaneum is not often seen in gardens, but is a ver^"^ 

 desirable dwarf-growing plant, with pretty pink flowers ; it is, how- 

 ever, a slow-growing variety, and rare in collections. 



Silene cpi/xdridentata is a very elegant dwarf plant with small 

 white flowers, but soon spreads out into a broad tuft when grown in 

 light soil. »S'i/''??e^>'/>/»7io is a rare species, and very bcautifid ; this 

 plant does best when planted between flat stones, and few peoj)]e arc 



