362 G. T. HARRIS ON 



or two places near Totnes, and near Meavy parsonage. A note, 

 however, states that a new station had been recorded "by an 

 unknown friend in April 1826, Gallow's Hill in Nottingham 

 Forest." These localities correspond with those given by Braith- 

 waite, which are presumably arranged in chronological order, 

 and the " unknown friend " of Withering would appear to be 

 Jowitt. Withering confused Schistostega osmundacea Mohr and 

 PterygopJiyllum {=^ Hypnum) lucens Brid., a very different plant, 

 and attributed to this species the luminous appearance peculiar 

 to Schistostega as well as Bowman's station, Rowter Kocks, 

 Derbyshire. Since Newbery's day so many records have been 

 made that it is now known to be a widely distributed moss, 

 twenty-two county and vice-county divisions from Cornwall to 

 Stirling possessing it in the British Isles alone (23). The lane at 

 Zele is on the northern confines of Dartmoor, and Dartmoor may 

 be considered a centre of distribution for Devonshire, for among 

 its tors and rocks it is abundant and widespread. It would 

 appear to thrive best in granitic areas, as it becomes increasingly 

 rare in Devonshire beyond the influence of granite intrusions. It 

 is not infrequent around Silverton (12), north of Exeter, a district 

 invaded by the granite of Dartmoor ; in East Devon it is quite 

 a rare moss. 



On Dartmoor it grows in narrow rocky crevices, principally 

 among the tors, in disused mine adits, and in old rabbit burrows 

 and fox holes. From very extensive observations of the habitats 

 on Dartmoor I have elicited the fact that these invariably face 

 north to east, while the moss itself in the majority of instances 

 occupies a position that gives it a northerly aspect. This observa- 

 tion is the result of the examination of dozens of localities on 

 Dartmoor in which compass bearings were taken. At my request 

 Mr. F. R. Rowley, F.R.M.S., of Exeter, noted the bearings of alt 

 the localities he found for this moss on Dartmoor during a month'& 

 holiday there, and found them to face north to north-east. An 

 area of Dartmoor in which this moss is particularly plentiful is. 

 the scarred and broken ground around the Vitifer tin mines. 

 In the old tin gullies that reach up nearly to the top of Birch Tor 

 rabbit burrows are so plentiful that "The Warren" is a local 

 appellation, and it gave me a very good opportunity of testing 

 the accuracy of the observation. In no instance did I find 

 Schistostega in a burrow facing south or west. One of the few 



