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Freshwater Flora

A list of warm spring flora recorded has been compiled below. 

Habitat conditions in open springs were found to generally favour the proliferation of an abundant and diverse aquatic plant flora (Knocksouna, Kilmallock; St. Gorman's, Enfield). These conditions included characteristics such as a shallow, small water body, where ample light for photosynthesis reached the spring bed, a slow flow of nutrient-rich water and usually a layer of organically rich mud substratum. The elevated water temperatures prevalent in warm springs might be expected to alter the growth cycle or morphological form of any macrophytic community present. However, any such influence was not apparent during this survey.

Several warm springs are now found in a highly modified state, some of which include those springs now used as holy wells which are housed in artificial well chambers. Some of these wells receive little or no direct sunlight (e.g. St. Patrick's Celbridge, St. Patrick's Morristown). Light regime played an important role in determining the poor floral community at these sites. In addition to the lack of direct sunlight, well management practices (e.g. the clearing of plant growth and any organic debris present) and or dumping / pollution, has directly resulted in a poorly developed or non-existent plant community at St. Patrick's Well (Celbridge), St. Patrick's Well (Morristown), St Bridget's Well (St. Margaret's) and Lady's Well (Mallow).

The floral component recorded during this survey can be broken in to the following groups:

1) Bryophytes: Aquatic liverworts have been recorded in Irish warm spring habitats in the past (Reynolds, 1998). Crystalwort (Riccia fluitans) was recorded during this survey at Knocksouna. Several mosses are important in Irish freshwaters and are often characteristic of certain habitats. Many species of moss, such as Fontinalis antipyretica (a leafy moss often found in both calcareous and acidic waters), are important as refuges for invertebrate species. Several moss species including Fontinalis antipyretica were recorded during this survey.

2) Charophytes: Species of Chara appear to be particularly adapted to hard water systems (Preston and Croft, 1997). Their perennial, compact low growth form and their provision of a winter refuge means they are usually associated with an abundant invertebrate community. Chara species were recorded from four of the eight sites visited during this survey, primarily indicating the highly calcareous nature of warm spring water.

3) Filamentous algae: Filamentous algae were recorded at five sites during this survey. The presence of luxuriant growth of filamentous algae can be indicative of elevated nutrient levels in water and associated quality problems. Growth of filamentous algae at warm spring sites was generally recorded as 'occasional'. However, an exception was the warm spring at Louisa Bridge. The filamentous algal species Cladophora was recorded as 'frequent' at Louisa Bridge and generally dominated the floral community. Louisa Bridge is a warm spring site suffering from a generally poor ecological status because of suppressed oxygen conditions and large scale dumping of organic and inorganic materials.

4) Higher plants: As described earlier, a well-developed community of higher plants was recorded at only two sites. This phenomenon was more a reflection of spring management practices than it was of any thermal influence. Natural or semi-natural conditions prevailed at Knocksouna and St. Gorman's where approximately 11 species of aquatic macrophytes were identified when water was present. Some aquatic plants of interest included the aquatic liverwort Riccia fluitans which is mostly found floating in sheltered shallow water of ponds, pools, and seepages and tends to be warm or nutrient enriched. Polygonium amphibium (Amphibious biswort), which can exist in either of two phenotypes depending on water conditions (recorded at St Bridget's and St Gorman's). Rorippa microphylla was recorded as abundant in both St Gorman's and Knocksouna and was present but rare in Mallow. This species is well distributed throughout Ireland and flourishes in many habitats from waters that are highly acidic to those that are calcareous.

Species list

Algae

Cladophora sp., Spirogyra sp., Closcerium sp., Batrachospermum sp.

Charophytes/ Stoneworts
C. vulgaris, Nitella flexilis, Charophyte sp. indet.

Bryophytes - Mosses and Liverworts
Fontinalis antipyretica, Brachythecium plumosum, Rhynchostegiella tenella, Riccia fluitans (Crystalwort)

Vascular Plants
Acorus calamus (Sweet flag), Alisma plantago, A. aquatica (water plantian), Apium nodiflorum (fool's water-cress)

Callitriche stagnalis, C. obtusangula 

Carex echinata (Sedges)  

Elodea canadensi (Canadian Pondweed)  

Hippuris vulgaris (Mares Tail) 

Iris Pseudacorus (Yellow Iris) 

Juncus bulbosa (Rush) 

Lemna trisulca (Ivy-leaved duckweed), L. minor

Mentha aquatica (Water mint) Menyanthes trifoliata (Bogbean) 

Oenanthe aquatica  (Water-dropworts)

Polygonium amphibium (Amphibious biswort)

Ranunculus sp. (water crowfoots) Ranunculus aquatilis 

Rorippa microphylla (Water cress)  

Rumex hydrolapathum (Water dock) 

Scirpus lacustris (Club rush)

Typha latifolia (Bulrush) 

Veronica catenata (Brooklime/Speedwell) 

Zannichellia palustris (Horned pondweed)  

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