﻿THE ORCHID REVIEW. [January, [904 



THE GERMINATION OF ORCHIDS. 



M. Noel Bernard has been studying the germination of species o 

 Cattleya and Lselia, and communicates the results of his work to a 

 recent number of the Comptes Rendus of the French Academy of Science 

 (vol. cxxxvii. pp. 484-485). Seeds of Cattleya and Laelia and their 

 hybrids germinate very freely under glass, and are usually sown in 

 damp sawdust. After about a fortnight, the embryos produce small 

 "spherules" or globular bodies, which are conspicuous by their green 

 colour. They remain for some time at this stage, and sometimes do not 

 develop further, the seeds sooner or later dying from the attack of a 

 parasitic mould. Under favourable conditions, however, after a varying 

 period, which may be as much as one or two months, growth com- 

 mences and proceeds steadily forwards. Germination is always slow and 

 irregular ; often after four or five months the most advanced plants are not 

 more than five millimetres high. These little plants are then top-shaped, 

 widened at the apex, where the terminal bud is formed. They are always 

 more or less covered at their basal point, to which the suspensor is attached, 

 by a filamentous endophytic fungus. M. Bernard's experiments have shown 

 that the penetration of this fungus is an essential condition in the germina- 

 tion of Orchid seeds, a point which had been previously suggested, but the 

 proofs now offered had not hitherto been obtained. 



Hybrid seeds from M. Magne, obtained by intercrossing Cattleya Mossia 

 and Laslia purpurata, were used, and details of the cultural methods 

 employed are given. M. Bernard found that if the seeds were completely 

 sterilised germination never progressed beyond a certain stage, but in the 

 presence of the particular fungus the seedlings developed in the usual way. 

 He was also able to cultivate this fungus on a nutrient medium separately, 

 and when sterilised germinating seeds were removed to a pure culture of 

 this fungus the mycelium rapidly penetrated the suspensor of the seedling, 

 and invaded the cells adjacent to the embryo, after which the seedlings 

 developed in the usual way. Parasitic fungi and bacteria, on the contrary, 

 rapidly destroyed the embryos. If the proper fungus is present germination 

 succeeds, but if its presence is prevented the embryo ceases to develop 

 beyond a certain stage. M. Bernard concludes that the embryo Orchid will 

 no more develop into a perfect plant without the assistance of the fungus 

 than an egg can go through its evolution without being fertilised. It may 

 be remembered that a similar "symbosis" has been pointed out in the 

 germination of seedling oaks and other plants. The identity of the 

 particular fungus is at present uncertain, but this point will be investigated 

 later on, and it will be extremely -interesting to have the point cleared 



