In Canada, Porter’s Twisted Moss grows on weathered, porous **calcareous rock** that is free of other plant competitors, particularly on vertical and steeply sloping or undercut faces and in pits or protected depressions. Porter’s Twisted Moss is **associated with calcium-rich rocks, and may therefore respond negatively to acidity**. These rock substrates include **limestone and dolostone cliffs and boulders**, which are typically linked to more basic (higher pH) conditions than siliceous rocks.

The report, citing Maiz-Tomé (2016), states: "The species grows in slightly acidic to basic water […]" and later that "Nymphaea odorata grows rooted in mucky or silty sediments in water up to six to seven feet deep and can survive in both acid and alkaline waters." This indicates that the American white water lily tolerates a broad pH range from slightly acidic through basic (alkaline) conditions.

The PLANTS Database entry for *Nymphaea odorata* (American white waterlily) describes the species’ wetland status but does **not specify a narrow pH optimum**, indicating that it occurs broadly in freshwater wetlands. American white waterlily is listed as a **facultative or obligate wetland species** across multiple U.S. regions, suggesting tolerance of the typical slightly acidic to neutral conditions of many ponds and lakes rather than a requirement for alkaline waters.

The study reports that different moss species show **species-specific differences in water chemistry (pH, EC, and TDS)** of the water they hold. It notes that some species of peat moss (e.g., *Sphagnum*) are **acidophytic since they acidify their habitat through hydrogen ion release**, while others increase Ca and Mg levels, altering ionic composition and nutrient availability. Measured pH associated with several mosses ranged from about **3.9 to 5.4**, illustrating that many bryophytes are adapted to **acidic to slightly acidic conditions**, though some can influence pH themselves.

The Fire Effects Information System entry describes water and substrate chemistry for ribbed bog moss, stating: "The pH of water, peat, and/or soil is usually **acidic to neutral** in mires with ribbed bog moss, although ribbed bog moss **tolerates mildly alkaline conditions**." It reports that the species occurs in bogs ranging from **pH 5.0 to 7.3** in Minnesota and was abundant on sites ranging from **pH 4.5 to 7.5** in Alberta peatlands, showing that at least some mosses naturally span from acidic to mildly alkaline conditions.

The USGS Nonindigenous Aquatic Species (NAS) fact sheet describes American white waterlily as occurring in ponds, lakes, and slow-moving waters but does not specify a numeric pH range. It emphasizes the species’ widespread native range and its establishment in many habitats, which is consistent with a broad tolerance for environmental variables such as pH.

Growth requirements: "White waterlily grows in both acid and alkaline waters when the water depth is 2–13 cm or less (Sinden-Hempstead and Killingbeck 1996, Wiersema 1997)." The document describes the species as occurring in a variety of water bodies and notes that dense growth "may alter water quality by creating low oxygen conditions beneath the canopy or by changing nutrient dynamics, pH levels, or light regimes." This indicates tolerance of a broad pH range rather than a narrow optimum.

The care guide for Syntrichia ruralis (twisted moss) lists its preferred soil pH as "5–7.5" and notes that this range supports optimal health for the plant. This indicates twisted moss tolerates moderately acidic to slightly alkaline conditions.

Encyclopaedia Britannica describes water lilies (family Nymphaeaceae) as aquatic plants that "grow in **still or slow-moving freshwater**" such as ponds and lakes. The entry does not discuss pH preferences, but notes their presence in typical freshwater habitats worldwide, which are often **slightly acidic to neutral**, rather than specifically alkaline.

The county fact sheet states that fragrant water lily (Nymphaea odorata) "grows in freshwater lakes, ponds and slow-moving streams and ditches." It further notes that "Fragrant water lily can tolerate a wide range of pH but prefers mucky to silty lake/pond bottoms." This describes the species as pH-tolerant without specifying a restricted acidic or alkaline preference.

The USDA Forest Service profile for white water lily explains that the plant "is generally found in quiet water up to 5 or 6 feet deep and is adapted to its aquatic habitat." It notes its rhizomes, floating leaves and flowers, but does not list a narrow pH requirement, implying broad ecological tolerance typical of a widespread aquatic species found across much of North America.

The Atlas of Florida Plants notes that *Nymphaea odorata* occurs in **ponds, lakes, and slow-moving streams**, but does **not list specific pH requirements**. Its distribution across a wide range of freshwater habitats in Florida implies that it tolerates **typical soft to moderately hard waters**, which are often slightly acidic to neutral rather than strongly alkaline.

NatureServe describes Nymphaea odorata as "occurring in lakes, ponds, streams, marshes, sloughs, and disturbed sites" and notes that it is globally secure. The habitat description emphasizes its presence in a wide range of quiet freshwater habitats but does not specify a particular pH band, which is consistent with a plant that tolerates both acidic and alkaline conditions.

In aquatic plant management manuals, Nymphaea odorata is listed among species occurring in "soft to moderately hard waters" with pH typically between 6.0 and 8.0. The species is not described as requiring distinctly alkaline conditions; instead, it is reported from a broad range of circumneutral freshwater habitats.

The UCF Arboretum plant profile lists soil type as "Base to Acidic" and farther down summarizes: "Wide pH range." The habitat description notes the plant is found in Florida freshwater environments such as ponds, lakes, and rivers. The combination of "Base to Acidic" and "Wide pH range" indicates that American white water lily is adapted to both acidic and more basic (alkaline) conditions.

The Extension guide for water lilies in garden ponds explains that hardy water lilies prefer water that is **still and relatively clear**, and situates them in typical garden pond conditions. It does not identify a narrow pH requirement but, consistent with ornamental pond guidance, implies that they are grown successfully in **standard pond water typically maintained around neutral pH**.

This regional botanical profile notes that White Water-lily (Nymphaea odorata) is "a floating aquatic plant common in quiet waters of marshes, ponds, and slow-moving streams" in the Adirondacks. It states that the plant "can grow in water depths up to about five or six feet" but does not identify a specific preferred pH, again suggesting that pH is not a strongly limiting factor within normal freshwater ranges.

A bryological study on moss species richness reports that many mosses occupy substrates with pH from about 4 to 7 and that some taxa extend into slightly alkaline conditions. The paper emphasizes that mosses, as non-vascular plants, often tolerate a wide pH range, and that their association with acidic substrates is frequently due to reduced competition from vascular plants rather than strict pH adaptation.

The Native Plant Society of Texas entry for Nymphaea odorata describes it as "one of the most common white water lilies." It notes that the flowers and leaves float on the water and that the plant is native to ponds and quiet waters. The page focuses on morphology, habitat and ornamental use but does not refer to a narrow pH preference, consistent with other sources describing broad adaptability.

The cultivation guide notes: "Mosses prefer growing on firmly packed acidic soils with a pH between 5.0 and 5.5 (actually alkaline soils over 7.0 for sun-tolerant moss)." It explains that while many mosses are associated with acidic substrates, certain species that tolerate full sun can grow well in soils with pH above 7.0.

The article states that the common belief that mosses prefer a pH between 5.0 and 5.5 is overstated. Quoting bryologist David Spain, it says: "Most mosses will colonize a much wider range of pH than other plants... since they do not draw nutrients from substrates, their need for a certain pH range is overstated." It also notes that moss is often found on acidic substrates because other plants are excluded there, not because moss cannot grow at higher pH.

The care guide states that Java moss can tolerate a wide range of water chemistry and that it "can tolerate a wide pH spectrum, from **slightly acidic (5.0) to mildly alkaline (8.0)**, allowing it to fit comfortably into most freshwater aquarium setups." This illustrates that some aquatic mosses are **flexible across both acidic and mildly alkaline conditions**, rather than being restricted to a single pH regime.

A field study of Syntrichia ruralis (twisted moss) reports its occurrence on both calcareous (lime-rich, often alkaline) and acidic rock substrates. The authors note that S. ruralis is "frequent on basic to slightly acidic rocks" and can tolerate substrate pH values from about 5 to just above 7, indicating ecological flexibility rather than a strict preference for alkaline conditions.

A summary of research on spring-dwelling mosses explains that the authors expected water chemistry to be a key driver of moss traits and found that mosses in **hard water (high in calcium carbonate)** springs had different traits than those in soft water. Specifically, mosses in hard water springs had **needle-like leaves, higher density and lower water absorption capacity**, suggesting adaptation to calcium-rich, more alkaline waters, whereas those in soft water springs showed the opposite traits.

This paper examines pH niches for a range of bryophytes and concludes that many moss species show broad tolerance, with realized niches often spanning 3 or more pH units. It highlights that the observed distribution is shaped by competition and moisture as much as by pH, and only a minority of species are confined to clearly alkaline waters or substrates.

This horticultural article states that Nymphaea odorata "thrives in still or slow-moving waters, making it ideal for ponds, lakes, and calm streams" and "grows best in water depths ranging from 1 to 4 feet." It discusses light, depth and climate zones but does not give a specific pH requirement, instead treating the plant as generally adaptable in typical pond conditions.

The grower’s care sheet for Nymphaea odorata lists quick-reference requirements such as "Sun: Full sun, 6+ hours of strong midday light" and recommended container size and depth. It does not specify a required pH range, implying that the species is compatible with the typical pH of ornamental ponds, which generally falls within the usual freshwater range from slightly acidic to slightly alkaline.

In freshwater ecology, many widespread macrophytes, including common water lilies such as Nymphaea odorata, are documented in limnology texts as tolerant of a broad pH range (approximately pH 5.5–8 or wider). They are often described as indicators of still or slow-moving freshwater rather than of a narrow pH band. Species-specific pH optima are not always sharply defined and can overlap considerably among different aquatic plants, which complicates claims that one species consistently occupies more alkaline water strictly because of pH adaptation.

A post about fragrant water lily notes that "The fragrant water lily can tolerate a wide range of pH, and prefers mucky to silty bottoms." This community-native-plant summary echoes government and academic descriptions that Nymphaea odorata is tolerant of varied pH conditions rather than restricted to either strongly acidic or alkaline waters.