Slender green feather moss (Hamatocaulis vernicosus)

Synonyms: Drepanocladus vernicosus
GenusHamatocaulis (1)
SizeWidth: up to 10 cm (2)

Classified as Nationally Scarce and is protected under Schedule 8 of the Wildlife and Countryside Act 1981 in Great Britain; it is listed on Annex IIb of the EC Habitats & Species Directive, and Appendix I of the Bern Convention (3).

Slender green feather moss is a straggling moss (4), which has green to brown erect shoots, with hooked tips, reminiscent of a walking stick (3). This trait is referred to by the scientific name Hamatocaulis, which derives from the Latin for 'hooked stalk' (5).

This moss has been confused in the past with similar species, but recent survey work has clarified its UK distribution (4). Although it has been recorded throughout Britain, it is frequent only in parts of north Wales and the north-west of England (4), and is rare in the rest of England and Scotland (3).

This species occurs in mineral rich mires (3), flushes and springs, and more rarely in lowland fens (4).

Little is known of the biology of this species. Mosses, hornworts and liverworts form a group of plants called bryophytes (3). Bryophytes lack many of the more complex structures of the higher plants, such as a vascular system, and flowers. They do not have roots, instead they have structures called 'rhizoids' which absorb water and anchor the plant to the substrate. All bryophytes have an interesting life cycle consisting of two main parts, called the gametophyte and sporophyte generations (6). Plants that are in the gametophyte stage can reproduce sexually. Male organs (antheridia) produce male sex cells or gametes called antherozoids, which actually move to the female sex organs (archegonia) (6) through water droplets (7). Fertilisation occurs and a plant develops called a 'sporophyte', which remains attached to the plant. The sporophyte releases spores from within a capsule; the spores disperse and develop into a new gametophyte stage plant (6).

This species has undergone a decline in the last century, but the severity of this decline is not clear because of widespread confusion with other mosses (3). Eutrophication and a decline in grazing are thought to have resulted in the loss of the species in East Anglia, changes in grazing, atmospheric pollution, forest creation and disturbance or drainage of mires are all thought to be responsible for the decline of this species in the rest of Britain (3).

A Species Action Plan has been produced for this moss under the UK Biodiversity Action Plan (UK BAP). This plan aims to maintain the current range of the species, and to increase populations where possible (8).

Information authenticated by Royal Botanic Gardens, Kew:

  1. National Biodiversity Network Species Dictionary (August 2002)
  2. Smith, A. J. E. (1996) The moss flora of Britain and Ireland. Cambridge University Press.
  3. Church, J. M., Hodgetts, N. G., Preston, C. D. & Stewart, N. F. (2001) British Red Data Books: mosses and liverworts. Joint Nature Conservancy Committee, Peterborough.
  4. JNCC 1393 Slender green feather-moss. SAC selection information. (August 2002):
  5. Latin Dictionary and grammar aid (August 2002):
  6. Mosses and Liverworts in Wales (August 2002):
  7. Egerton, H. & Jones, F. (Eds.) (1998) Nature Encyclopedia. Dorling Kindersley, London.
  8. UK BAP Species Action Plan (August 2002):