346 JOURNAL OF THE EOYAL HOETICULTUEAL SOCIETY. 



for the green fringe which is often seen all round the stones in the lower 

 part of the walls in Malta. 



Besides the bulbs thus formed in a vertical line, at all depths, this 

 Oxalis often produces runners above ground. They only occur, however, 

 on luxuriant plants, such as those growing by the watercourse in the 

 Wied Encita, or in the rubbly ground within the ditches of the fortifica- 

 tions, &c, or, again, in the rich soil of the orange-gardens at Cairo. The 

 runners, however, do not root like those of strawberries, but produce bulbs 

 at the nodes, so that a number of young plants can be produced at a short 

 distance from the site of the parent plant. 



It certainly affords one of the most extraordinary instances of a very 

 extensive multiplication, and that solely by the vegetative system, indicating 

 the fact that the assumption that intercrossing of flowers by fertilization 

 is necessary to ensure vigour is totally unfounded.* It might be thought 

 that, as it is only the short-styled form which exists, the pollen might 

 readily fall upon and pollinate the stigmas, thus assuring at least self- 

 fertilization. It undoubtedly does fall down upon them, as there are ten 

 anthers well filled with pollen, which stand above the stigmas ; but 

 whether the latter be perfect or not has not been ascertained. At all 

 events, seed is never set, so it is practically impotent. 



The double form is very common, though not to the same extent, in 

 Malta, and, as mentioned above, it occurs in N. Africa as well as in the 

 Atlantic Islands. It often has rather smaller leaves, but I do not think 

 this can be relied upon as a fixed character ; the petals are sometimes 

 more than fifty in number, and are orange-yellow, those of the ordinary 

 form being golden yellow. 



It may be added that the tendency to produce bulbs is to some extent 

 dependent on the growth of the plant. The generally infertile calcareous 

 ground of Malta, where it grows by the roadsides, &c, tends to induce the 

 formation of bulbs, for they are much fewer on a plant which grows 

 luxuriantly, when it spends its energies in the development of flowers and 

 foliage. Thus, in the orange-gardens of Cairo it does not spread as in 

 Malta, but the individual plants grow to a great size. 



As an illustration of the production of bulbs under a check to vitality, 

 I may add that when specimens are being pressed for a herbarium, a 

 quantity of bulbs are always formed at the same time at the crown of the 

 vertical rhizome ; the vital energy, being checked above, now expends 

 itself in the formatiou of bulbs until the whole plant is dead. 



A final word on Oxalis comiculata, L. This species is very wide- 

 spread, and botanists of the last century often allude to its extension in 

 the Mediterranean regions. It is a native of Malta, but at the present 

 time only to be found in gardens. It was the opinion of the late Dr. Gulia, 

 Professor of Botany in the University of Malta, that Oxalis cemua had 

 driven it away from the open ground. In Cairo, 0. comiculata is abundant 

 in the Esbekiyeh public gardens, where it occupies large patches in the 

 "turf," the latter being principally composed of Gyperus rotundus and 

 Lippia nodiflora, which it appears to displace. In the botanic garden at 

 Cairo, the two species were actually growing intermixed as intruders in a 

 border, and 0. cemua was certainly overwhelming the 0. comiculata. 

 * Just as is the case with Elodea canadensis in this country. 



