122 Mr. A. H. Church. On the Occurrence of [Apr. 26, 



turn, var. GliamcBcyparissus, 54 per cent, of alumina. These results, 

 with others by Arosenius, are conclusive as to the occurrence in 

 notable proportion of alumina in the ash of certain Lycopodia. But 

 when Solms-Laubach records in the ash of Selaginella hraussiana, 

 A. Br. (erroneously described as Lycopodium denticulatum) the occur- 

 rence of 2 per cent, of alumina, we may regard the observation as 

 likely to be incorrect ; the same remark applies to the supposed dis- 

 covery of a similar proportion of this earth in the ash of Aspidium 

 filix-mas and of Athyrium filix-fcemina. And when the ashes of these 

 plants were examined by modern methods, and with all the pre- 

 cautions which improved analytical processes require, then alumina 

 can scarcely be recognised qualitatively in them. In one of the 

 species of Selaginella, however, which I examined, I found a weighable 

 trace of alumina, namely, 0*26 part in 100 parts of the ash. This 

 plant, grown at Kew, was Selaginella martensii, var. robusta (the 

 compacta of A. Braun). The ash was large in amount, namely, 

 11*66 per cent, in the dry plant; besides the 0*26 per cent, of alumina 

 in it, there was 41*03 per cent, of silica (' Chemical News,' vol. 30, 

 1874, p. 137). In pursuing this inquiry, I examined, with every 

 possible precaution to ensure exactness, three British species of 

 Lycopudium all obtained from the neighbourhood of Shap in West- 

 moreland, as well as the single species of Selaginella which belongs 

 to Britain. This last plant, now known as Selaginella spinulosa, 

 A. Br., was formerly called Lycopodium spinulosum ; my supply 

 came from Largo Links in Fifeshire. The following figures represent 

 the percentages which I obtained : — 



100 parts of ash 

 contained 



Percentage of ash f * ^ 



in dry plant. A1 2 3 . Si0 2 . 



Lycopodium alpinum . 3*68 33*50 10*24 



L. clavatum 2*80 15*24 6*40 



L.Selago 3*20 7*29 2*53 



Selaginella spinulosa ....... 3*44 none 6*67 



All these results pointed unmistakeably to the conclusion that 

 while alumina was an important mineral constituent of many species 

 of Lycopodium, it was practically absent from Selaginella. This dis- 

 tinction was confirmed by an analysis of L. cernuum f which I subse- 

 quently made. This species belongs to a group of the genus Lyco- 

 podium, quite distinct botanically from the group to which L. alpinum 

 and L. clavatum belong, and also distinct from the L. selago group 

 and the L. complanatum group. The following are the figures yielded 

 by this plant : — 



