Mr. W. Mitten on the Mosses and Hepatica of Sussex. 313 



45. 21 mutabile, Bruch. 



Didymodon brackydontius, Wils. Eng. Fl. 

 Common on the Downs ; and at Shoreham, growing plentifully on 

 the scanty humus between the shingle, exposed to immersion at very 

 high tides ; always sterile. 



46. T. crispulum, Bruch. 



Didymodon crispulus, Wils. Eng. Fl. 



Nearly as common as the last, but like it confined to the chalk and 

 the sandy sea-shore, and barren. 



47. T. rubellum (Hoffm.), Rabenh. 



Weissia curvirostra, Hook, and Tayl. Eng. Fl. 

 Frequent on walls and roofs, and on the ground about the roots of 

 trees. 



48. T. rigidulum, Sin. 



Didymodon rigidulus, Hedw. Eng. Fl. 

 Rare : in small quantity at Henley Hill and about Hurstpierpoint. 



49. T. trif avium, Sm. 

 Didymodon trifarius, Sw. Eng. Fl. 



Frequent on the Downs ; growing on the earth in tufts about the 

 roots of trees ; it is also common on sandstone and on mortar in walls 

 built of sandstone, but rarely fertile. 



50. T. tophaceum, Brid. 



On a wet sandy bank near Hurstpierpoint ; at Hastings on and 

 above the cliffs near the Dripping Well, and on walls at Midhurst. 



51. T. convolutum, Brid. 

 Didymodon nervosus, Hook, and Tayl. 



On the cliffs between Brighton and Beachy Head, and at Hastings. 



Genus 4. Barbula, Hedw. 



52. B. abides, B. et S. 

 Tortula rigida, Eng. Fl. 



Common about the Downs, and less frequently on clayey banks. 

 This is the T. rigida of the Flora of Tunbridge Wells. 



53. B. ambigua, B. et S. 



On a sandy bank near Hurstpierpoint, where it grew very sparingly 

 in 1849. 



54. B. rigida, Schultz. 

 Tortula enervis, Eng. Fl. 



In small quantity about a chalk-pit at Newtimber near Hurstpier- 

 point. 



