ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 327 



in presence of organic matter. Two radish plants were grown in a 

 culture solution containing 10 p.c. saccharose. One remained in contact 

 with air, and at the end of 121 days had started to form fruits. The 

 other remained under the same conditions for 70 days, and was then 

 inclosed in air free of C0 2 for 41 days. The leaves were small and 

 the flowers still unopened. The cortex was thick, but lacked the normal 

 sclerenchyma, while some of its cells were multinucleate. There was 

 much secondary wood, but the vessels were small and feebly thickened. 

 Starch was very abundant, being found even in the epidermis. The 

 leaves were thin and had few air-spaces, the mesophyll being closely 

 packed and full of starch. Similar results were obtained with a solution 

 containing 5 p.c. glucose and 2 p.c. asparagin. 



In short, it seems that plants deprived of C0 2 can make more use of 

 organic substances than when under normal conditions ; also, the dif- 

 ferences observed are very much like those found between subterranean 

 organs and homologous aerial organs. 



Symbiosis of Orchids and Fungi/* — Noel Bernard, in his work on 

 the endophytes of Cattleya, Phalmiopsis, and Odontoglossum, finds that 

 each species prefers its own endophyte ; but he has sometimes suc- 

 ceeded in causing the embryos of a certain species to enter into com- 

 bination with each of two different fungi. Experiments were made 

 with hybrid seeds of Lcelia Mozart, Brassavola Digbyana, and with pure 

 seeds of Vanda tricolor, using the endophytes of Cattleya, Phalcenopsis, 

 and Odontoglossum. Lcelia Mozart and Brassavola Digbyana gave good 

 results with the endophyte of Cattleya, on a jelly substratum ; but with the 

 endophyte of Phalamopsis, on a substratum of cotton, the tubercle was 

 larger and absorbing hairs more numerous. Vanda tricolor, cultivated 

 with the endophyte of Phalcenopsis on a substratum of elder pith, 

 attained full development of the tubercle, and had produced three 

 leaves and a root in three months. With Odontoglossum the period of 

 tuberisation was much prolonged, and there were no leaves at the end of 

 five months. It would appear that successful results depend on the 

 nature of the substratum and on the time of infection. The rapidity 

 and mode of growth depend on the nature of the endophyte. 



General. 



Irish Topographical Botany.f — R. LI. Praeger gives a supplement 

 to his " Irish Topographical Botany," published in 1901, which embodies 

 the results of the work of the last five seasons. The net total number 

 of species and sub-species to be added to the county lists is 814. Twenty- 

 four plants have been added to the Irish list as a whole. These are 

 mostly critical forms, and include seven Brambles and six Hawkweeds ; 

 three are not yet recorded elsewhere. A new fumitory, Fumaria 

 purpurea, has been detected both in Great Britain and Ireland, and 

 Glyceria festucaformis, a Mediterranean grass, as yet unknown in Great 

 Britain, has been found at several places in County Down. 



• Comptes Rendus, cxlii. (1906) pp. 52-4. 



t Proc. Roy. Irish Acad., xxvi., sect. B (1906) pp. 13-45. 



