A new WGI member from Romania recently asked us what we know about Nymphaea lotus forma thermalis, which grows in thermal springs there. "Not much," was our answer. Not a water gardener herself but with interest sparked by a visit to the habitat, Ana Veler presents the most research and compiled information available anywhere from any source. Though probably incomplete, Ana and WGI invite input and discussion of her article that may lead to greater knowledge of this interesting relic.

Nymphaea lotus var. thermalis at Baile 1 Mai
Photo by Ana Agache

Nymphaea lotus up north,

by Ana Veler
Bucharest, Romania
with thanks to Carlos Magdalena, RBG Kew

Click images to enlarge

According to a steady trickle of records starting with the field notes of a Hungarian botanist from the late 1700s, a small population of Nymphaea lotus was sheltered by particularly mild and constant thermal springs at a temperate 47 degrees northern latitude. The place is a group of small ponds and river at Petea, in northwestern Romania. The plant is known as Nymphaea lotus forma thermalis.

Is 10,000 years a long time?

Not necessarily. The fossil record of Nymphaeales covering the last 115-125 million years *i suggests that ancient plants were similar enough to the current Nelumbo and Nymphaea to be instantly recognizable *ii, more then could be said about the continents the plants clung to. If not much changed from the waterlily's point of view, isolated populations could be old by geologic standards with no readily visible sign to tell them apart from the rest. Inasmuch, the early records of the plants at Petea point out their similarity with Nymphaeas on the Nile. Any subtle differences and their significance remain a tantalizing research project.

Climate alone should have kept Nymphaea lotus at Petea isolated from the closest subtropical population for at least ten thousand years. Lake Petea is a young, mainly Holocene, aquatic system which did not originate before Pleistocene times *iii. The water in the geothermal reservoirs at Oradea and Felix spas was dated by the 14C method, at approximately 20,000 years of age *iv.

Slow history, fast

The existence of the thermal ecosystem at Petea has been known and exploited as a natural spa for a couple hundred years *v. The area has been a conservation hot spot for more than a century.

The earliest known mention of the hot springs at Felix Bai as "Termae Varadienses" -- the hot springs of Oradea -- is a property award document written in 1221 now in the Vatican library. Nicolaus Olahus, a local scholar, mentions them in 1536. N. lotus did not surprise anyone then -- few would have seen both tropical and eastern European waterlilies to realize the kinship.

The hot springs started to be used as a health spa between 1700 and 1721 by an intrepid physician, Felix Heldres, whose name was borrowed by the locality to date. In 1731 a report on the springs is published. Permanent spa installations start around 1760 -- in 1763 a doctor's notes mention bathing basins. The first spa-dedicated buildings are raised 1766-72. The spas were advertised at the World Exposition in 1896.

Amid this context of interest in local nature, the earliest note of the N. lotus enclave is made by Kitaibel (1799) *vi. At the time of his travel and first edition of the botanical atlas, Sânmartin had been reestablished officially as a permanent rural settlement for less then 40 years after around two centuries of hiatus *vii. Considering such historic conditions, any direct link between the closest habitat of the species in its typical climate zone (the Nile Delta) and Oradea area before 1800 require vivid imagination.

The idea that the N. lotus at Petea could have been preserved by the heat of the thermal springs from pre-ice age times when it would have been spread throughout a warmer Europe was proposed in 1907 by Janos Tuzson *viii and later reinforced by the identification of other endemic species sharing the habitat.  

Some Names and Numbers

What: Nymphaea lotus (alternatively: Nymphaea lotus forma thermalis)
a tropical night blooming waterlily

Status: Protected species *xxv. The area of the reserve is state-owned, in the legal custody of Crisuri County Museum whose department of natural history dedicates its main publication and significant attention to the plants.

Where: Petea Natura 2000 *xxvii
conservation site, Sânmartin, Oradea County, Romania


Area: 51.0 hectares (126 acres) of protected area. Petea Lake is small, somewhat over 1 square kilometer (.4 square mile).

Coordinates: 47°0"43', 21°58"42'

Altitude: med/max/min: 146.0/166.0/132.0 (479/545/433’)

Climate. moderate-continental

Temperatures *xxviii:
Annual average: 10-11 C (51 F)
Annual average minimum: 1-2 C (35 F)
Coldest month: January
Annual average maximum: 20 C (68 F)
Warmest month: July
Historic minimum (Oradea): -29.5 C (24 Jan. 1942) (-21.1 F)
Historic Maximum (Diosig): 40 C (18 august 1952) (104 F)
Number of days/year with freezing temperatures (daily minimum of at most 0 C) 100-150
Number of summer days/year (daily maximum at least 25 C) 80-100
Number of tropical days/year (daily maximum at least 30 C) 15-35

Annual rainfall (mm): 50-70
Number of rainy days per year (days with any rainfall) 115-130

Thermal springs: The nature reserve includes three ponds and a rivulet with thermal water at roughly constant 30 C temperature *iii. Geothermal boreholes and natural hot springs in Felix Spa have surface temperatures ranging from 35 to 55° C. The relevant "Felix Spring" has an emerging temperature of 32 C. All wells produce artesian discharge with a total mineral concentration under 1g per liter. The geothermal water from the Felix Spa reservoirs is neutral (pH 6 at 20°C). *v

The place: Sânmartin *xxix is a rural township 7 kilometers away from Oradea, holding the joint administration of six villages and the Felix and 1 Mai spa resorts.

The locality has changed hands historically and as a result is also referred to in the literature as Bischofsbad (German) and as Püspökfürdö (Hungarian). 

Drilling to supplement the debit of the main hot spring started in 1885. Recently, water extraction has been capped in order to preserve the natural supply to the protected area and the thermal springs *ix.

The first moves to protect the Romanian Nymphaea were by botanist and then government minister in charge with public education Alexandru Borza *x. In 1932 the Council of Ministers *xi declares the plant a natural monument and the Petea rivulet a protected area. The record of various interventions and conservation since the late 1940s describes the progressive retreat of the small thermal waterway and lake(s) supporting N. lotus *xii.

Lake Petea
Image from

The local museum, legal custodian of the Petea Reserve, has promoted the species since the beginning of the last century; the values of the region's natural endowment and the charismatic waterlily feature prominently in the recent program to revamp the institution. Predictably, local civil society organizations with any environmental concern have also taken up the flag *xiii.  

To give a sense of scale for the economy of the reserve's neighborhood: Sânmartin, the small homonymous township with other five villages in joint administration next to the protected area, counts a permanent population of 8000. Tourism, the main local industry, is slowly moving away from struggling publicly owned and privately managed facilities toward smaller, private sector operations with more local flavor. Tourism at Felix is arguably in doldrums *xiv with about 30,000 tourist arrivals per year - half the numbers of 1990. Barring any sudden motivation for development, the situation has a good chance to persist as such *xi. In 2007, Sânmartin spent Euro 3m on infrastructure -- a large investment, relatively *ix.

As the place is changing, the local economy may take up and price beyond local budget constraints some of the "services" that nature has provided free of charge since the last ice age: the continuous geothermal water flow and the very separation from competing tropical species that have supported the geothermal habitat are no longer entirely "free" and their dependence, financial and otherwise, on the local economy can only increase.  

< Resort at Baile Felix - Image from http://www.magest.ro/ 

One may wonder why other warmth-loving plants have not been kept up north along with Nymphaea all this time. However, nothing prevents invasive newcomers today. On such a time scale, any conservation "fashion" is a short, consequential blip: in 1948 tropicals were introduced intentionally at Petea. Later on, invasive aquarium tropicals followed suit on their own. Their removal has been the object of repeated conservation efforts since *xv.

Such conservation slippages, water management and broader local development issues are recognized threats facing Nymphaea lotus forma thermalis today. The popularity of all local waterlilies as cut flowers is another. Surprisingly, this is still a minor survival industry impervious to regulation, not a budding business of sustainable cultivation locally. Perhaps not yet *xvi?

There are good signs and bad: the serious administrative and policy interest in the "N. lotus forma thermalis" name is good. That the lily was taken into account by recent water regulation is better. That tourists and sometimes the press cannot tell one waterlily at Felix from another is worrisome, as informed popularity is what should keep the plants relevant in front of future challenges.

Nymphaea lotus forma thermalis at Pedea
Photo by Ana Agache
It is somewhat sad that some visitors confuse the glowing pink buds of Nelumbo nucifera planted in plain sight at Felix Bai with the local legend they are expecting to be as conspicuous as its preceding reputation. The bit of information that the Nymphaea flowers are not to be expected by day is somewhat obscure apparently. (Editor's Note: It is also sad and potentially confusing that the web sites of Baile Felix and Sânmartin display photos that are clearly of hardy waterlilies instead of N. lotus forma thermalis.)

However important, awareness can only just hope to rearrange priorities at any given time. The nature reserve remains relatively isolated from the economy of local development today, while immediate proximity to an intimate relation with the geothermal source makes deliberate isolation tenuous. This relationship has yet to develop. Plans for organized access await. The local legend is yet to be made as conspicuous in person as its preceding reputation.

A matter of taxonomy

Seeing a tropical plant up north may have been terribly surprising around 1750. History resonates today. Is this all there is? After all, Nymphaea lotus grows in any warm water with proper physical characteristics -- no matter where the heat or the original plants might come from *xvii. Also, varieties of Nelumbo nucifera and Euryale Ferox are found at northern latitudes in the Russian far east without such obvious geothermal support *xviii.

The significance of the peculiar isolation of Nymphaea lotus at Petea may even get dwarfed by traditional popularity and prominent conservation status. What is worth having a wayward population of something preserved in autarchy for ten thousand years?

GRIN Taxonomy places N. lotus forma thermalis as synonomous with N. lotus, though classification as a distinct variety of N. lotus was assigned by Tuzson in recognition of the particular location and conditions *xix. The extent of alternative justification will likely continue to be a matter of further investigation.

Certainly, this is not the only taxonomic slot attributed by historic considerations awaiting quantifiable criteria. Consider the status of Nelumbo komarovii, and the two species of night blooming Nymphaea: N. lotus and N. pubescens *xx. Could it be N. pubescens rather than N. lotus that is growing at Petea?

Awaiting further qualifications from the biology, morphology or genetics of the plant population, it remains quite surprising that the geologic scenario at Petea should remain completely singular *xxi.

Threats and promise

The degree of differentiation from current tropical populations of N. lotus is not known in sufficient detail to answer the question whether N. lotus from Petea must be treated as a separate variety for conservation purposes. Is it sufficient to assume that reintroducing N. lotus from any current tropical location in the event of near extinction at Petea will make little difference? No question that the local phenotype should always be used for conservation purposes and ex-situ propagation is a breeze *xxii. The entire nature reserve is a relatively small lake: if risks of extinction are to be hedged against the area of distribution -- a common kind of back-of-the-envelope calculation, the whole Petea setup is difficult to conceive as a twenty thousand year steady arrangement going on another twenty thousand.

Baile Felix and Baile 1 Mai
Image from http://www.turismbaile1mai.com/ 

Today none of the botanical gardens in Romania have the plant *xxiii. N. lotus forma thermalis is held in the collections of the botanical gardens in Bonn and at Kew. Communication with the custodians of the Petea nature reserve may be expected in the future *xxiv.

The area has recently become part of the European Union's biodiversity conservation framework to which Romania adheres as a new member state. This is a good time to evaluate the research interest of the Nymphaea population at Petea in the broader context of the natural history, biodiversity and taxonomy of Nymphaea lotus.

Endnote: Please note that the analysis and opinions formulated in the article belong to the author and are not in any way related to their respective institutions. All data sources mentioned in the text are available per request, subject to the copyright status of each source.


[i] See:www.victoria-adventure.org/water_gardening/history/timeline.

[ii] In Romania, lower Jurassic and Eocene fossils of Nymphaea have been recorded at Bihor for example.

[iii] Personal communication with Prof. Marton Venczel, director of the Natural History department of Tara Crisurilor Museum, the institutional custodian of the Petea reserve. Cited in Mathias Harzhauser, Oleg Mandic, ‘Neogene lake systems of Central and South-Eastern Europe: Faunal diversity, gradients and interrelations’, Paleo, December 2007

[iv] Dorina Maria Farcas, ‘Therapeutic Effects of the Geothermal Water in the Felix Spa, Romania’, Proceedings World Geothermal Congress 2005, Antalya, Turkey, 24-29 April 2005

[v] www.bailefelix.ro

[vi] Waldstein, F. De Paula Adam Graf Von & P. Kitaibel, ‘Descriptiones et icones plantarum rariorum Hungariae’ pub. Vienna, Matthias Andreas Schmidt, (1799), 3 volumes, Folio (465 x 332mm)

The book is conveniently listed in the catalog of the library at Kew. The first two volumes of the folio are made available in the public domain in electronic format by the Digital Library of the Royal Botanical Garden in Madrid.

The associated herbarium is now dispersed; partial collections are located at the Hungarian Natural History Museum and the National Museum in Prague.

Mention of the plant is made twenty years later in the better known compendium he edited, but it is unlikely that he had further direct evidence at hand: Candolle, Augustin Pyramus de. Regni vegetabilis systema naturale, sive Ordines, genera et species plantarum secundum methodi naturalis normas digestarum et descriptarum; auctore Aug. Pyramo de Candolle, pub. Parisiis [etc.] sumptibus sociorum Treuttel et Würtz, 1818-21. At the Kew Library.

[vii] Sânmartin Town Hall, local history monograph online: www.sanmartin.ro/Monografie/dimensiunea%20istorica.htm

[viii] Tuzson János: Tuzson J.: "A Nymphaea lotus csoport morfologiája és rendszertani tagolódása". A "Mathematikai és Természettudományi Értesíto" 1907.

[ix] The exploitation of the thermal flow at Felix Spa is regulated by the National Agency for Mineral Resources.

[x] Borza, Al. 1924. Floarea de lotus de la Oradea, Rev. Stiintifica V. Adamachi, Iasi, 9:1, p. 20 to 22

Borza, Al. 1931

Borza, AL 1942. Le richezze naturali della Romania e la loro protezione, Lucrarde Inst. Geog. Univ. Din Cluj la Timisoara, VII, p.1 to 22

[xi] Published in Jurnalul Consiliului de Ministrii No.148 / 1932. The same legislation minted the first two species with the recently defined (1930) status of “natural monument” and set several protected areas. It should be noted that the government led by N. Iorga at the time (1931-1932) had to contend with very serious difficulties well outside the realm of environmental conservation, so fitting the promotion of endemic nature within the political motivations of the time makes the story all the more interesting.

[xii] See a short review in: Sebastian Viorel Jurca, Betsy Hoffmeister, ‘The Plight Of The Romanian Thermal Waterlily’. Water Garden Journal, Spring 2001.

N. lotus forma thermalis
grown by Carlos Magdalena at the Royal Botanic Gardens Kew

Tuber and underwater foliage

Young pad

Young pad reverse

More mature pad

More mature pad reverse

[xiii] A casual search through the Romanian press yielded a couple of reports about such action: producing leaflets and getting voluntary manpower to take out invasive algae from some warm water ponds.

[xiv] Marcel Rosca, Dorina Farcas, Geothermal Health and Tourist Spas in Romania, University of Oradea Publishing, 2001

[xv] Various ‘Nymphaea’ Journal articles cited in Sebastian Viorel Jurca , Betsy Hoffmeister, The Plight of the Romanian Thermal Waterlily, Water Garden Journal, Spring 2001.

Morossy A, 1999, Some observations on silting and eutrofization of Petea stream, Nymphaea XXVII, Oradea, p. 139 - 144.

Oldea GH., Petea Lake and Stream – Draft document for protection measures, implementation and impact monitoring for the restoration and conservation of the thermal lotus population at Petea, Bihor. Institute of Biological Research, Cluj, 1993.

[xvi] ...excluding any competition for the geothermal water resources as the nature reserve. For a survey of geothermal energy use in the region see: Marcel Rosca, ’Combined Geothermal and Gas District-Heating System, City of Oradea, Romania’, Proceedings World Geothermal Congress, Kyushu - Tohoku, Japan, May 28 - June 10, 2000.

[xvii] One case in Europe: It is tempting to think that Kitaibel’s observations may have inspired the introduction of tropical waterlilies in a Hungarian thermal lake a hundred years later when Sándor Lovassy, a professor at the Keszthely School of Economics, began experimenting with naturalizing N. lotus plants brought from India and Africa into Lake Hévíz in 1898. A pink variant became naturalized and was subsequently adapted into the city's coat of arms.

Another in the US: thermal springs used for heating homes in Boise, Idaho, also supply water gardens today. Geothermal sources have been used for a century on Historic Warm Springs Ave.

[xviii] Alexander Nijman, Saving the World's Coldest Growing Lotus, Water Gardeners International, Volume 1, No. 2, May 2008.

[xix] Cornelia Oltean-Cosma, 1977, The Biology of Nymphaea lotus L. forma Thermalis (D.C.) Tuzs., from Bãile 1 Mai - Oradea, Nymphaea V, Oradea, p. 365 - 380.

[xx] A leading taxonomist suspects N. lotus and N. pubescens may be the same when they get to molecular studies but keeps them separate largely for historical reasons.

[xxi] It is conceivable that new research on the thermal ecosystem at Petea and N. lotus could connect with the larger but thin domain of research on geothermal wetland ecosystems. Another question, another day …

[xxii] ... in view of recent propagation at Kew; review note by Carlos Magdalena.

[xxiii] The Botanical Garden in Bucharest used to hold N. lotus forma thermalis. See: Constantinescu, M. (1977), "Some notes on the behavior of some tropical aquatic plants in greenhouse conditions. I. Nymphaea lotus forma thermalis, Sagittaria subulata, Ceratopteris thalictroides Unele insemnari asupra comportarii unor plante acvatice tropicale in conditii de sera", I. Lucr. Gradina Botanica Bucuresti Acta Botanica Horticultura Bucuresti: 63-65.

[xxiv] For current conservation issues, the following are comprehensive sources:

Custody Award File for Petea Natura 2000 Site (4110), Radovet Dorina, Bihor County Water Administration Agency (APM Bihor)

Morossy A, 1999, Some observations on silting and eutrofization of Petea stream, Nymphaea XXVII, Oradea, p. 139 - 144.

Oldea GH., Petea Lake and Stream – Draft document for protection measures, implementation and impact monitoring for the restoration and conservation of the thermal lotus population at Petea, Bihor. Institute of Biological Research, Cluj, 1993.

[xxv] Relevant EU and national legislation:

Council Directive 2006/105/EC of 20 November 2006 adapting Directives 73/239/EEC, 74/557/EEC and 2002/83/EC in the field of environment, by reason of the accession of Bulgaria and Romania; For EU legislation pertinent to Natura2000 in Romania, see the EUR27 version of the Interpretation Manual of European Union Habitats EU 27, European Commission, DG Environment, July 2007

Law 213 / 1930 (Instates the concept of "natural monument" for species and sites of particular interest for conservation)

Jurnalul Consiliului de Ministrii No.148 / 1932 (names the first natural monuments in the basis of the 1930 law, including N. Lotus forma Thermalis)

[Government of Romania] Ordonanta De Urgenta Nr. 57 din 20 iunie 2007 privind regimul ariilor naturale protejate, conservarea habitatelor naturale, a florei si faunei salbatice

[Parlamentul României] Legea nr. 5 / 2000 pentru aprobarea Planului de amenajare a teritoriului national, M.O.12.04.2000

HCJ Bihor nr. 19 / 1995

[xxvi] Nymphaea Journal, annual, see cited in references.

[xxvii] Natura 2000 is a network of nature protection areas established in1992 as the centrepiece of EU nature and biodiversity policy: ec.europa.eu/environment/nature/natura2000/index_en.htm

Petea Natura 2000 Site Fiche: n2k.nationalparks.ro/natura2000/siturile/view_site.html?oid=1267

[xxviii] According to Sanmartin Town Hall, based on observations between 1896 – 1955. Current meteorological records are produced by the Oradea Weather Station.

[xxix] www.sanmartin.ro/  

WGI ONLINE Journal Table of Contents

Water Gardeners International
Home | Join WGI | Members' Exclusive | Gateway to Water Gardening