Lichenes. — Bryophyten. 67 



23 on Picea, and among those the only Danish epiphyllic liehen, 

 Biatorina niicrococca Körb. 



On Fagus, Carpinus, Pinus montana, Querciis, Fraxtnus and 

 Alniis crustlike lichens are found on the trunk, most amply 

 on the latter species. On young Fagus, which keep their leaves 

 during winter, no lichens can thrive, nor on the trunk of trees, 

 growing in chalky ground, while the}" grow thick so quickly. When 

 Fagus is growing in good mouldy soil, no lichens can thrive on the 

 ground on account of the continued work of the earthworms; and 

 only a few crustlike lichens are found on the trunks, but if Fagus 

 is growing in acid and moorlike soil, the trees will grow more 

 scattered and the trunks will be covered by a rieh Vegetation of 

 bushy lichens. the author enumerates 42, and on the ground 4 species 

 are found, which has been formerly mentioned as growing in acid 

 soil beneath Picea. 



The author enumerates 15 species on Carpinus and 26 on Pinus 

 montana Quercus has the greatest number of lichens of all the trees 

 of the forest on its trunk, 63 species are growing there, but no 

 lichens are found on the ground beneath the Quercus, where the trees 

 are growing densely. On Fraxinus the author has found 37 species, 

 on Alnus 25 and on Betula 25; only the latter of the said trees 

 allows so much light to penetrate its erown, that the leafy lichens 

 are able to live on its stem. On Populus the author has found 

 38 species; for this tree as also for Fraxinus it is of the greatest 

 significanee if they have been planted in alleys or in stock. 



In the 6*^ and last chapter the author discusses all the lichens, 

 living on stones. On common chalk no liehen was ever found in 

 Denmark, on other sorts of limestone the author enumerates 36 

 species. He gives a very detailed description of the lichens on rocks, 

 firsth^ Verrucaria halophila and Segestrella leptotera at the water's 

 edge, and afterwards the black contiguous crust of the greasy Ver- 

 rucaria rupestris Sehrad. subsp. niaura Wahlb., covering the rocks 

 above the uppermost waterline, and so on tili the most dry localities; 

 he altogether mentions 138 spec. of lichens, living on rocks The 

 lichens of the stony plains are greatly infiuenced by the tear and 

 wear of the flowing sand, to which they are exposed, and their 

 cortex must continue to grow from within in order to make up for 

 the outside tear. On stones in fresh water only one species, Verru- 

 caria hydrela Ach. is found, always in Company with the snail 

 Ancylus ßuviatilis. I. Lind (Copenhagen). 



Barnes, C. R. and Land, W. J. G., The origin of the cupule of 

 Marchantia. (ßotan. Gaz. XL VI. 401—409. Dec. 1908.) 



The cupule is found to arise in an entirely different manner 

 from the air Chambers, in the development of which periclinal walls 

 soon make their appearance. In the young cupule the epidermal 

 cells divide only anticlinally, thus produeing slim eells the central 

 ones of which give rise to the gemmae while the marginal ones 

 develop into the scale-like rim of the cupule. A gemmiparous cell 

 divides periclinally twice, so as to prodviee a basal cell, stalk cell 

 and gemma cell. Periclinal divisions of cells surrounding a cupule 

 soon cause them to outgrow the cupule and thus to make it appear 

 as a depression, although it is strictly epidermal in origin. The mode 

 of formation of the cupule in Lunularia is similar, except that the 

 rim develops on one side only. M. A. Chrysler. 



