Aloina ambigua
Common Name: Tall Aloe-Moss, Conservation Status - Least Concern (Campisi, et. al., 2019)
Although generally listed as separate species, some have argued that A. aloides and A. ambigua should be considered the same species (Campisi et al., 2017).
Appearance and Identification
Aloina ambigua has a very similar appearance to Aloina aloides, and therefore, also resembles succulents like the Aloe vera plant. Each shoot is 2-5mm tall, and comprised of dark green, hooded leaves with incurved and un-toothed margins. Like many acrocarpous mosses it grows primarily in scattered turfs with no organised colony structure, patches of which can look green or brown when viwed from afar. (Hill et al., 2017; Pilkington, 2010).
A. ambigua is a dioecious species, and from October to April it is very common to see large reddish capsules on the plants (Hill et al., 2017). These capsules usually have pointed, but hairless calyptra, and a basal membrane separating the peristome teeth from the main body of the capsule. When mature the capsules are held upright by long, reddish-orange seta (Pilkington, 2010a).
Similar Species:
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Aloina aloides- A. ambigua has a ring of cells at the base of the peristome teeth, the basal membrane, is not found in A. aloides and can be seen when the capsules are viewed from the side (BIBS, n.d.; Pilkington, 2010b). Additionally, A. aloides is common in Ireland, Wales and Scotland and can grow at altitudes above, while A. ambigua is not present in Scotland or above 200m and, rarely found in Ireland or Wales, (Hill et al. 2017, Pilkington 2010a; Pilkington 2010b).
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Aloina brevirostris - Not only significantly smaller than A. ambigua (1-2mm) but also incredibly rare in the UK, it only occurs in England and Scotland, the latter of which A. ambigua has yet to be recorded in (Hill et al., 2017; Pilkington, 2010c). It also only grows in a limited selection of habitats and subtrates, it cannot be found on rocks, gravel or building, or in coastal dunes and inland cliff habitats like A. ambigua can (Hill et al., 2017). Its leaves are also, shorter, narrower, and more rounded than those of A. ambigua (Pilkington, 2010c).
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Aloina rigida - Not only significantly smaller than A. ambigua (1-2mm) but also incredibly rare in the UK. Unlike A. ambigua it can be found in Scotland and above 200m of altitude, but not in coastal dune habitats (Hill et al., 2017; Pilkington, 2010c). Its leaves are also, shorter, narrower, and more rounded than those of A. ambigua (Pilkington, 2010c).
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Small Pognatum sp. - The majority of Pogonatum species found in Britain and Ireland are an order of magnitude larger than A. ambigua, and even specimens which are similarly sized can be distinguished by their toothed leaves and hairy calyptra. Additionally, all Pogonatum are calcifuges and cannot grow in calcium rich soils which A. ambigua frequents (Hill et al., 2017; Pilkington, 2010a )
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Polytrichum juniperinum - It is only particularly small specimens that could be confused, as on average this species is significantly larger than A. ambigua (Hill et al., 2017). The main physical difference is that P. juniperinum has a much longer, drawn out leaf tip which is often red tinged (Pilkington, 2010a). However, the two species are usually found in the complete opposite habitats as A. aloides requires high calcium, basic soils, while, P. juniperinum prefers acidic, low calcium soils (Hill et. al., 2017).
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Polytrichum piliferum - It is only particularly small specimens that could be confused as on average this species is significantly larger than A. ambigua (Hill et al., 2017). The main physical difference is that P. piliferum has a much longer, drawn out leaf tip which fades to colouress near the ends (Pilkington, 2010a). Additionally, the two species are usually found in the complete opposite habitats as A. aloides requires high calcium, basic soils, while, P. piliferum prefers acidic, low calcium soils (Hill et. al., 2017).
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Distribution
A. ambigua is widespread and common across most of Europe, with the largest populations occurring in the south and south-east of this continent, with the exception of North Macedonia were the species is yet to be recorded. As you travel north the species becomes much rarer; its range does not extend into Scotland, Lithuania, Estonia, Latvia, Norway, or Finland, and it can only be found in the southern tip of Sweden (Campisi et al., 2017). Finally, while in the past this species could be found in Slovakia, since 2020 it has been listed as regionally extinct here (Hodgetts & Lockhart, 2020). This is not the only country where A. ambigua is regionally threatened, it is considered Near Threatened in Madiera, Luxembourg, Bulgaria, and Hungary, Endangered in Sweden, Ireland, Northern Ireland, and the Czech Republic, Highly Endangered in Austria, and Critically Endangered in Romania (Hodgetts & Lockhart, 2020). It can also be found in many regions outside of Europe, including North Africa (including Macaronesia), South-West Asia (Azerbaijan,Kyrgyzstan, Tajikistan, Türkiye, and Turkmenistan), South-West United States of America, Mexico, and Australia (Campisi et al., 2017; Erata et al., 2020; Igantov et al., 2006). A. ambigua is considered a southern-temperate species, so across its range it can be found in shrublands, temperate grasslands, pasturelands and urban areas between 0-2100m above sea level (Campisi et al., 2017; Hill et al., 2017).
Recent sightings for A. ambigua in the UK have been concentrated in the south, south-east and east of England, with a large amount of observations appearing in East Anglia (Blockeel, 2014). This species cannot be found in Scotland, and is rare in Ireland, Wales, and the Channel Isles (Blockeel, 2014; Hill et al., 2017). It is most commonly found in areas with sparsely vegetated, chalky soils, but in Cambrideshire it is found primarily on sand and gravel, and in northern England it inhabits Magnesium Limestone deposits. There are also reports from Kent of A. ambigua being found on green roofs (Blockeel, 2014).
UK Altitudinal Range: 0-220m (Blockeel, 2014).
Habitat and Ecology
A. ambigua is a perennial moss, and is therefore found throughout the year. However, because mature capsules are required to distinguish it from A. aloides, the best time to look for this moss will be between October and April, when mature capsules are most common (Hill et al., 2017; Pilkington, 2010a).
A. ambigua likes to grow in well-lit areas, at least 40% illumination during the summer, with substrates which are well-drained but not extremely dry (Hill et al., 2017). It needs soils which are relatively low in nitrogen (infertile), but are overall basic and rich in free calcium carbonate. As a result it is common in lime-rich, lowland areas such as chalk pits, chalky grasslands, calcareous clay and sand dunes (Blockeel, 2014; Pilkington, 2010a). Due to its preference for bare, sparsely vegetated, or disturbed soils in some parts of its range this species is threatened by forest encroachment (Blockeel, 2014; Campisi et al., 2017). In the UK it has been recorded on the following substrates; worked rock (e.g. brick and mortar), soil on rock, soil, gravel and sand, and in the following environments; coastal dunes, inland cliffs and rocky outcrops, inland areas with low levels of vegetation, low density buildings such as field walls, and farm buildings, and finally extractive industry sites (Hill et al., 2017).
Associated Species: Barbula unguiculata, Didymodon acutus, Microbryum rectum, Pseudocrossidium hornschuchianum and Tortula lanceola.
Regional Threat Level
British Red List - Regionally classified as Least Concern with a currently stable population (Callaghan, 2022), but because it is only found in 88 hectads across the UK it is considered a nationally scarce species (Callghan, 2022; Pescott, 2016).
Irish Red List - Regionally endangered in Ireland due to its severely fragmented populations and its both heavily restricted and currently declining area of occupancy here (Hodgetts & Lockhart, 2025). It is also considered nationally rare, having been found in just 2 hectads since 1970 (Hodgetts & Lockhart, 2013).
References
Blockeel, T. J. (2014). Aloina ambigua. In T. J. Blockeel, S. D. S. Bosanquet, M. O. Hill, & C. D. Preston (Eds), Atlas of British and Irish Bryophytes (Vol. 2). Pisces Publications.
British and Irish Bryological Society. (n.d.). Aloina aloides. British and Irish Bryological Society. British Bryological Society. https://www.britishbryologicalsociety.org.uk/learning/species-finder/aloina-aloides/
Callaghan, D. A. (2022). A new IUCN Red List of the bryophytes of Britain, 2023. Journal of Bryology, 44(4), 271–389. https://doi.org/10.1080/03736687.2023.2185393
Campisi, P., Cogoni, A., Garcia, C., Hodgetts, N., Kucera, J., Lara, F., Lüth, M. & Schröck, C. 2019. Aloina ambigua (Europe assessment). The IUCN Red List of Threatened Species 2019: e.T84534696A87771585. Accessed on 15 September 2026.
Erata, H., Batan, N., Özen, Ö., & Alatas, M. (2020). Contributions to the bryophyte flora of Şalpazarı and Tonya districts (Trabzon, Turkey). 26(1), 71–79.
Hill, M. O., Preston, C. D., Bosanquet, S. D. S., & Roy, D. B. (2017). BRYOATT - Attributes of British and Irish Mosses, Liverworts and Hornworts. Centre for Ecology and Hydrology.
Hodgetts, N. G., & Lockhart, N. (2013). Rare and Scarce Bryophytes of Ireland. 110, 12–26.
Hodgetts, N., & Lockhart, N. (2020). Checklist and country status of European bryophytes – update 2020. National Parks and Wildlife Service.
Hodgetts, N., & Lockhart, N. (2025). Bryophytes (Mosses, Liverworts & Hornworts). Ireland Red List No. 14. National Parks and Wildlife Service, Department of Housing, Local Government and Heritage.
Ignatov, M., Afonina, O., & Ignatova, E. (2006). Checklist of mosses of East Europe and North Asia. Arctoa, 15, 1–130. https://doi.org/10.15298/arctoa.15.01
Pescott, O. (2016). Revised lists of nationally rare and scarce bryophytes for Britain. 115, 22–30.
Pilkington, S. (2010a). Aloina ambigua. In M. Lawley, I. Atherton, & S. Bosanquet (Eds), Mosses and liverworts of Britain and Ireland: A field guide (First Edition, p. 473). British Bryological Society.
Pilkington, S. (2010b). Aloina aloides. In M. Lawley, I. Atherton, & S. Bosanquet (Eds), Mosses and liverworts of Britain and Ireland: A field guide (First Edition, p. 472). British Bryological Society.
Pilkington, S. (2010c). Aloina brevirostris/rigida. In M. Lawley, I. Atherton, & S. Bosanquet (Eds), Mosses and liverworts of Britain and Ireland: A field guide (First Edition, p. 471). British Bryological Society.
Written By: Lucy Hudson Last Updated: 18th September 2026