Eggenberg, S., L. Champoud, M. Leibundgut, C. Parisod, L. Wyss & G. Kozlowski (2023). Calamagrostis lonana (Poaceae): a new grass species from the Pennine Alps (Switzerland). Candollea 78: 1–9. In English, English and French abstracts.
Calamagrostis lonana Eggenb. & Leibundg. (Poaceae) is described as a new alpine grass species from the Pennine Alps. Unlike other Central European Calamagrostis Adans. species, it is only 13–18 cm high and has so far been found only on the high plateaus of the Pas de Lona, along the Torrent de Lona. Compared to similar species, the panicle is only faintly tinged purplish, has remarkably short panicle branches, and thus remains narrow and elongated even when open. The spikelets show callus hairs that only reach about halfway up the lemmas, and these have a short, dorsal awn. The species is probably closely related to the arctic C. stricta (Timm) Koeler, which has only a few relict occurrences in Central Europe. However, it is morphologically well separable. The morphological description of the species is completed by information on the distribution, habitat, soil conditions, and potential threats of C. lonana.
Submitted on April 15, 2022. Accepted on December 14, 2022. First published online on March 28, 2023.
Eggenberg, S., L. Champoud, M. Leibundgut, C. Parisod, L. Wyss & G. Kozlowski (2023). Calamagrostis lonana (Poaceae): une nouvelle espèce de graminée des Alpes pennines (Suisse). Candollea 78: 1–9. En anglais, résumés anglais et français. DOI: http://dx.doi.org/10.15553/c2023v781a1
Calamagrostis lonana Eggenb. & Leibundg. (Poaceae) est décrite comme une nouvelle graminée alpine des Alpes pennines. Contrairement aux autres espèces de Calamagrostis Adans. d'Europe centrale, elle ne mesure que 13–18 cm de haut et n'a été trouvée jusqu'à présent que sur les hauts plateaux du Pas de Lona, le long du Torrent de Lona. Par rapport aux espèces proches, la panicule n'est que faiblement teintée de violet, possède des branches paniculaires remarquablement courtes, et reste donc étroite et allongée même lorsqu'elle est ouverte. Les épillets présentent des poils sur leurs callus qui n'atteignent qu'environ la moitié des lemmes et ceux-ci ont une courte arête dorsale. L'espèce est probablement proche de l'espèce arctique C. stricta (Timm) Koeler, qui n'a que quelques occurrences reliques en Europe centrale. Cependant, elle est morphologiquement bien distincte. La description morphologique de l'espèce est complétée par des informations sur sa distribution, son habitat (dont les conditions de sol) et les menaces potentielles qui pèsent sur C. lonana.
Introduction
During fieldwork in the alpine floodplains below the Pas de Lona (Val d'Anniviers, Valais, Switzerland, Fig. 1), a grass species was found by one of the authors (ML) which, based on its flower structure, is close to the taxon Calamagrostis stricta (Timm) Koeler according to Central European determination keys. However, the extraordinarily small growth habit and some morphological details of the flowers differ greatly from the forms of C. stricta described so far in Central Europe. The grass is inconspicuous and flowering stems only appear in late summer or autumn, explaining why it might have been overlooked until now. The comparison of collected plants with herbarium specimens of Calamagrostis Adans. from northern Europe revealed a similarity with arctic forms of C. stricta, especially with the often small-growing subspecies C. stricta subsp. groenlandica (Schrank) Á. Löve, a taxon with a distribution across the whole Arctic from North America to Eurasia.
Calamagrostis is a globally distributed genus within tribe Aveneae of the family Poaceae. In its traditional concept, it contains over 250 species, with high number of species in some mountains of the northern and southern hemispheres (e.g. Andes, Himalayas). The 1-flowered spikelets are arranged in spread or contracted panicles and have a densely haired callus, the hairs of which can reach the length of the lemma or even exceed it (Conert, 1998). Many species have a small axillary process (rachilla) above the floret (e.g. C. arundinacea (L.) Roth, C. varia (Schrad.) Host, C. stricta) and are treated as a separate genus Deyeuxia Clarion ex P. Beauv. by several authors (e.g. Simon, 1993; Phillips & Chen, 2003; Zhengyi et al., 2016). However, recent genetic analyses (Saarela et al., 2017) support a polyphyletic genus, indicating that Deyeuxia should be placed in synonymy. On top of confirming the suspected polyphyly of the whole Calamagrostis-Deyeuxia complex, Saarela et al. (2017) prove its proximity to the genus Agrostis L. (Phillips & Chen, 2003) as well as genera with multi-flowered spikelets such as Deschampsia P. Beauv. or Trisetum Pers. (Saarela et al., 2017). The relationships inside the complex do not seem to be fully resolved yet and thus call for description of the segregating variation towards accurate inferences. In this study, we describe a new species, C. lonana Eggenb. & Leibundg., endemic to the Pas de Lona which differs morphologically, ecologically, and genetically from the other Calamagrostis taxa known from central and northern Europe.
Material and methods
All morphological and ecological investigations of the new species were carried out by measurements in the alluvial plain of the Torrent de Lona (Grimentz, municipality of Anniviers, Pennine Alps) and through herbarium specimens collected there. Further observations were made on cultivated material at the Botanical Garden of the University of Berne and on herbarium specimens at G. Most observations and measurements were made on fresh material from 20 different individuals. Comparison with related species was made by studying the literature (Hess et al., 1967–1972; Conert, 1998; Fischer et al., 2005; Aiken et al., 2007; Elven et al., 2011; Tison & De Foucault, 2014; Parolly & Rohwer, 2016; Lauber et al., 2018; MÜller et al., 2021), supplemented by own measurements on fresh material (Calamagrostis stricta from Federsee, Upper Bavaria and Pontarlier, Franche-Comté). Morphological characters of C. stricta subsp. groenlandica were retrieved from Flora of Iceland (Löve, 1983), Flora of the Russian Arctic (Tolmachev et al., 1995), Flora of Russia (Fedorov, 1999), Norsk Flora (Lid, 2005), Flora of the Canadian Arctic Archipelago (Aiken et al., 2007), and Svalbardflora (Elven et al., 2023).
The ploidy level of individuals of Calamagrostis lonana, as well as other Calamagrostis taxa from nearby locations in France and Germany, was elucidated using flow cytometry (Bourge et al., 2018). Accordingly, leaf material of C. lonana from six samples collected in the field and two samples grown ex situ at the Botanical Garden of the University of Berne was silica-gel dried and sent for analyses to the Plant Cytometry Services (Didam, The Netherlands, www.plantcytometry.nl) to estimate genome size as compared to external standards (i.e. Allium schoenoprasum, 2c = 15,03 pg; Clivia miniata, 2c = 35.77 pg; Monstera deliciosa, 2c = 8.90 pg; Ophiopogon planiscapus, 2c = 11.90 pg of DNA). Three further samples of Calamagrostis stricta collected in each of the locations of La Censure (France), Grand Mont (France), Corne du Marais (France), Görbelmoos (Germany), and Federsee (Germany) were similarly treated and compared with samples of C. lonana. All estimates of DNA content were compared with published genome sizes in Smarda et al. (2019) and Zonneveld (2019) to assess the ploidy level of each sample.
In order to estimate the extent of the population, the plains and basins from the Lona area between Becs de Bosson (3148 m) in the North and Sasseneire (3253 m) in the South were explored several times and at different times of the year between 2018 and 2021. For the ecological studies, six vegetation surveys were carried out, covering the entire population in the alluvial plain of Lona. Of these, all moss species were determined at two sites. For soil examinations samples were taken at two sites. Root mass and rooting depth were studied in soil samples where Calamagrostis lonana was the only vascular plant. The soil type was determined on the basis of the reference method of Agroscope (Agroscope, 2020). Content of humus, clay, and silt was determined in field-moist samples or with moistened fine soil samples. For the pH measurement, the soil was dried at 40° C and sieved. Then, 20 g of soil was mixed with 50 ml of demineralised water and measured with pH strips.
The bioclimatic data were derived from the MeteoSwiss standard value maps (Meteoswiss, 2022).
Key to Central European Calamagrostis species (based on Müller et al., 2021)
1. Awn of lemma clearly protruding from spikelet 2
1a. Awn of lemma not protruding from spikelet 3
2. Leaf discolor (blue-green, dull adaxially; dark green, glossy abaxially); awn protruding 2–3 mm from spikelet; callus hairs sparse, c. 
as long as lemma
C. arundinacea
2a. Leaf concolor (blue-green, dull on both sides); awn protruding c. 1 mm from spikelet; callus hairs 2/3 to as long as lemma C. varia
3. Callus hairs distinctly shorter than lemma; ligule of upper stem leaves 0.5–2(–3) mm long 4
3a. Callus hairs 1–2 times as long as lemma; ligule of upper stem leaves (2–)3–12 mm long 5
4. Plant 10–20 cm high; ligules 0.5–1 mm long; panicle 2.4–5.5 cm long C. lonana
4a. Plant 30–120 cm high; ligules 2–3 mm long; panicle 8–20 cm long C. stricta
5. Ligule (2–)3–4 mm long; leaves conspicuously shiny below; lemmas 5-veined 6
5a. Ligule (4–)5–12 mm long; leaves dull on both sides; lemmas 3- or 5-veined 7
6. Plant bright to dark green; culms with 3–5 nodes, mostly unbranched; leaves smooth, lax; awn clearly visible, dorsally inserted on lemma C. villosa
6a. Plant light to grey-green; culms with 5–8 nodes, often branched; leaves stiffly erect, rough; awn short, inconspicuous, terminally inserted on lemma C. canescens
7. Glumes 6–8 mm long; awn terminally inserted on lemma; ligule (4–)5–6 mm long C. rivalis
7a. Glumes 4–6 mm long; awn dorsally or terminally inserted on lemma; ligule (4–)6–12 mm long 8
8. Callus hairs about as long as lemma; lemma 5-veined; leaves 5–8 mm wide C. phragmitoides
8a. Callus hairs longer than lemma; lemma 3-veined; leaves 5–15 mm wide 9
9. Plant bright green; glumes subequal; awn dorsally inserted on lemma; panicle erect, 15–25 cm long; leaves 8–15 mm wide, with rough margins; ligule (4–)6–9 mm long, glabrou. C. epigejos
9a. Plant blue-green; upper glume ¾ as long as lower one; awn terminally inserted on lemma; panicle drooping, 10–30 cm long; leaves 5–8 mm wide, rough on both sides and along margins; ligule (6–)8–12 mm long, hair. C. pseudophragmites
Taxonomy
Calamagrostis lonana Eggenb. & Leibundg., sp. nov. (Fig. 2, 3).
Holotypus: Switzerland. Valais: commune d'Anniviers, Plateau de Lona, 2588 m, 12.X.2019, Champoud & Eggenberg s.n. (BERN!; iso-: G [G00414405]!, SION!).
Calamagrostis lonana Eggenb. & Leibundg. differs from all other Central European Calamagrostis species by its small size: plants are smaller than 20 cm whereas other Calamagrostis species reach (30–)50–150 cm high. Like C. stricta, its callus hairs are distinctly shorter than the lemma and the awn is not protruding from the spikelet but differs by its short panicle with very short branches, short and often glabrous ligule, almost glabrous glumes, and very short anthers.
Perennial, stoloniferous, light to grey-green grass with loose but deep-reaching root system, with extravaginal shoot initiation. Culms solitary, glabrous, (10–)13–18(–22) cm high, erect, hairy towards the inflorescence, with 1–3 glabrous nodes; sheaths 1–5 cm long, glabrous. Ligules 0.5–1 mm long, glabrous abaxially or pubescent towards the tip. Leaf blades 80(–120) × 2–3(–3.5) mm, scabrous adaxially, glabrous abaxially, mostly enrolled. Inflorescences a dense panicle, (2.4–)3.1–3.7(–4) cm long, gradually spreading, soon contracting after anthesis; panicle branches 1–3(–4) from main axis, 1–6 mm long, short ciliate; spikelet stalks 0.5–2 mm long. Spikelets 2.5–3.2(–3.6) mm long, lanceolate, 1-flowered, light to grey-green, mostly with a purplish tinge towards the tip. Glumes narrowly lanceolate, long acuminate, the lower 2.6–3.1 mm long, 1-veined, glabrous, the upper 2.7–3.4 mm long, 3-veined, the prominent median vein often ending in an erect tip, fimbriate dorsally, otherwise glabrous; callus short, rounded, covered with hairs 1–1.4 mm long; axillary process tiny, 0.3–0.5 mm long, hairy, sometimes absent. Lemmas 2.1–2.4(–2.7) mm long, almost as long as the glumes, 5-veined, pubescent, ragged distally and ciliate like the veins; awn 1.5–1.9 mm long, straight, erect, ciliate, inserted c. 0.6 mm above the lemma base. Paleas 1.3–1.6 mm long, delicate-skinned, glabrous. Anthers 0.9–1.4 mm long, light yellow. Ovaries 0.2 mm long, remaining immature, narrow, with two terminal styles and feathery stigmas c. 1 mm long.
Etymology. – The epithet lonana refers to the name of the Lona plateau in the Pennine Alps (Valais), where the species was found in 2018.
Distribution. – Based on multiple visits of the Lona area, Calamagrostis lonana seems to be restricted to the alluvial plain of the Torrent de Lona and has not been found elsewhere to date. The plain lies at an altitude of 2580 m and extends along the Torrent de Lona, which flows in a west-easterly direction. It is about 720 m long and 200 m wide at its widest point. The distribution area of C. lonana is located within this alluvial plain with a maximum extension of 600 × 150 m. Within this area, several subpopulations of C. lonana could be found. They are very unevenly distributed and dissimilar in density. It cannot be excluded that further localities will be reported from other high altitude alluvial plains in the Pennine Alps.
Ecology. – The large alluvial plain of Lona shows a mosaic of different habitat types which is typical in dynamic alpine alluvial plains (Fig. 4). In addition to vegetation-free sand and gravel banks, initial alluvial vegetation (Caricion bicolorisatrofuscae), calcareous springs (Cratoneurion) and transitions to fens and transitional bogs (Caricion fuscae, Caricion davallianae, and Caricion lasiocarpae) can be observed. The vegetation classification of the occurrences of Calamagrostis lonana was done by the six releves shown in Table 1. The plot size was 10 square metres for all releves. The abundance was estimated using the Braun-Blanquet cover scale. There is usually an extraordinarily high cover of the moss layer at the sites where C. lonana is growing, a feature that is quite striking and constant. The following moss species were identified: Bryum pseudotriquetrum (Hedw.) G. Gaertn. et al., Calliergon giganteum (Schimp.) Kindb., C. richardsonii (Mitt.) Kindb. ex G. Roth, Campylium stellatum (Hedw.) Lange & C.E.O. Jensen, Palustriella falcata (Brid.) Hedenäs [dominant], Philonotis calcarea (Bruch & Schimp.) Schimp., Polytrichum juniperinum Hedw., Scorpidium cossonii (Schimp.) Hedenäs, and Warnstorfia exannulata (Schimp.) Loeske [dominant].
Due to the stratification of the vegetation (dominance of mosses) and the species composition of vascular plants and moss species, the assignment to the habitat type “calcareous spring formation” (Cratoneurion) is most likely. Typical species are Bryum pseudotriquetrum, Palustriella falcata, Philonotis calcarea and the vascular plants Agrostis stolonifera L., Arabis subcoriacea Gren., and Saxifraga aizoides L. which were often found in the vicinity of the vegetation surveys. The habitat of Calamagrostis lonana can thus be relatively well characterised. It is almost exclusively found in sites with low vascular plant cover and dominance of mosses.
The bedrock across the Lona plateau shows a diversity of different sediment types with both limestone-rich and limestone-poor sediments. In the alluvial plain we measured an average soil pH value of 6.5. The value was confirmed by laboratory measurements of soil samples. The high pH values of the organic soils of the alluvial plain can be explained by widespread calcareous sediments in the area. The examined soil profiles of Calamagrostis lonana growth sites always show a similar structure: a 10–15 cm thick moss layer (Fig. 3) is directly followed by a layer of grey alluvial loam more than 50 cm deep, intermixed with dead mosses probably from earlier inundations. The pH value remains unchanged over the entire profile depth (pH 6.5). Roots of C. lonana were found both in the moss layer (Fig. 3) and in the alluvial loam and can be detected down to a depth of about 40 cm.The root mass of Calamagrostis in a more closely examined soil sample was between 0.11 g (top layer) and 0.02 g or 0.04 g (lower layers) per 100 g of soil material. Whether during inspections at the beginning of August, in September or at the beginning of October the soil was always found to be completely water saturated.
The climate conditions are typical for dry central alpine areas with annual precipitation sum of only approx. 1000 mm (Meteoswiss, 2022). Most of the annual precipitation falls in summer, with a maximum in July. The annual mean temperatures of around 0° C are characteristic of the alpine belt, monthly averages rise to 6° C in summer (Meteoswiss, 2022). However, the basin form of the alluvial plain regularly leads to the formation of cold air depositions, so that temperatures in the alluvial plain are probably well below the mean temperatures of the area. Geomorphological landforms also reveal periglacial conditions across the whole Lona plateau. Mean temperatures are low and frost can occur throughout the year.
Phenology. – Flowering late summer (from August) and fruiting early autumn (from September).
Threats. – It can be assumed that the high plateaus of Lona have been used for grazing by sheep and cattle for a long time (Bätzing, 2015). The herds can move freely, there is no fencing. From late summer, when the slopes begin to dry out, the herds often gather in the green and fresh alluvial plains and the alluvial plain of the Torrent de Lona is exposed to increased trampling in late August and September. Therefore, the question arises to what extent the population of Calamagrostis lonana might be seriously damaged by trampling and grazing. The trampling impact on the plain is obvious, and tracks remain for a long time. The trampling tracks reveal a lower disturbance in mossy and Cyperaceae-dominated parts of the plain, the sites where C. lonana thrives most. These parts seem to be less attractive for the herds. Judging from the current situation, it does not seem necessary to fence out the alluvial plain. However, long-term monitoring of trampling is recommended.
Notes. – With its short, hairy axillary process, short callus hairs, and long lemmas, Calamagrostis lonana belongs to subgenus Deyeuxia. In central Europe, this subgenus includes the species C. arundinacea, C. varia, and C. stricta. The short, straight awns show a close relationship to C. stricta (Greene, 1980; Escalona, 1988), but it differs from this species in having smaller habit, shorter spikelets with shorter callus hairs, and shorter anthers (Table 2). As in C. arundinacea and C. varia, the spikelets have an axillary process, which distinguishes it from other Central European Calamagrostis species. However, this axillary process is very short in C. stricta (up to 0.5 mm long). Calamagrostis lonana differs from C. arundinacea and C. varia by the short, straight, dorsal awn, which is usually shorter than the lemma. In C. arundinacea and C. varia, the awn is basally inserted, geniculated, and largely exceeding the lemma. Calamagrostis lonana differs from all other Central European species by its small habit, which it also maintains in cultivation conditions. Important morphological characteristics are compared in Table 2.
The Arctic forms of Calamagrostis stricta show greater morphological plasticity than the Central European taxa, especially C. stricta subsp. groenlandica that shows similarities with the new species. According to literature (see Material and methods), C. stricta subsp. groenlandica is a variable species concerning the habit and the panicle length, displaying panicles as short as (3–)4 cm long. However, the panicles often remain contracted (spreading at anthesis in C. lonana), the callus hairs are usually more than 1/2 of lemma length (less than 1/2 of lemma length in C. lonana), the ligule is (0.5–)1.5–3(–6) mm long (0.5–1 mm long in C. lonana), and the glumes are more or less scabrous (glabrous or fimbriate on the keels in C. lonana).
Based on its morphology and cytology, the taxon found in the Lona alluvial plain belongs to the Calamagrostis stricta aggregate (syn. C. neglecta). The aggregate is part of the boreal and arctic flora with relict occurrences in Central Europe. Morphologically, the aggregate is very variable and therefore the taxonomy of the whole complex is controversially discussed. Calamagrostis lonana shows the same tetraploid level as all other non-apomictic taxa (2n = 28, x = 7; Elven et al., 2023) and differs from higher-ploidy taxa collected in and around the Alps. Despite the tiny axillary process, Saarela et al. (2017) place other tetraploid forms of C. stricta aggregate close to C. canescens (Weber) Roth and C. villosa (Chaix) J.F. Gmel., i.e., to species that do not possess an axial process. However, the subspecies that often shows small growth, C. stricta subsp. groenlandica, lies outside this clade (Saarela et al., 2017), which implies a clearer delimitation from C. stricta. Further genetic studies should better resolve the C. stricta aggregate and provide more clues to the taxonomic position of the new species found in the alluvial plain of Lona.
The flower organs develop very late. Anthers and ovaries with feathery stigmas could be observed from the end of September, but no fertile pollen was observed. Conversely, the species shows a strong growth of underground runners. In cultivation, the species shows especially strong vegetative growth and forms dense, vigorous mats within one growing season.
The 2n-genome size estimates obtained by flow cytometry varied between 7.33 pg and 8.10 pg of DNA for samples of Calamagrostis lonana, perfectly matching estimates for tetraploid Calamagrostis taxa (2n = 28) published in the literature (Smarda et al., 2019; Zonnefeld, 2019). In contrast, all other samples of presumably C. stricta collected across nearby locations in France and Germany presented genome size estimates ranging from 14.39 pg to 16.50 pg, rather matching decaploid taxa of Calamagrostis with 2n = c. 70 chromosomes.
Table 1.
Six vegetation releves showing the co-occurrence of Calamagrostis lonana Eggenb. & Leibundg. with other vascular plants. Species names according to Juillerat et al. (2017). [Abbreviations: imm. = immature; r = very low abundance; + = low abundance, cover < 5 %; 1 = high abundance, cover < 5 %; 2 = cover 5–25 %; 3 = cover 25–50 %]
Fig. 2.
Calamagrostis lonana Eggenb. & Leibundg. A. Habit with stolons within the moss layer; B. Inflorescence (contracted panicle); C. Section of inflorescence with adjacent panicle branches; D. Spikelet peduncle with glumes; E. Glume and palea with callus hairs and awn (dorsally inserted). [Drawings: S. Eggenberg]
Fig. 3.
Calamagrostis lonana Eggenb. & Leibundg. A. Habit of the aerial parts with moss cushion of Warnstorfia exannulata (Schimp.) Loeske. B. Upper root space in the moss layer. [Photos: S. Eggenberg]
Table 2.
Comparison of morphological characters between Calamagrostis lonana Eggenb. & Leibundg. (own measurements) and the Central European C. stricta (Timm) Koeler (measurements retrieved from Hess et al., 1967–1972; Quinger, 1987; Conert, 1998; Müller & al., 2021; Parolly & Rohwer, 2016).
Acknowledgements
During the research, the authors were able to count on the support of various persons and institutions. Our first thanks go to Norbert Schnyder for his support in the identification of the mosses. We thank the herbaria of Berne (Katja Rembold) and Geneva (Pierre-André Loizeau, Fred Stauffer) and the Botanical Garden of Berne (Markus Fischer, Silvan Glauser) for making their infrastructure available to us. We thank Peter Wandeler from the Natural History Museum Fribourg (NHMF) for the financial support of the genetic analyses. We thank Philippe Juillerat and other members of the Info Flora team for the valuable discussions. We thank Yann Clavien, head of the nature conservation department of the Canton of Valais, for his interest in the new endemic species. He was interested from the beginning and accompanied us to the field. Kathrin Fritsch from NABU Naturschutzzentrum Federsee and Yorick Ferrez from Conservatoire botanique national de Franche-Comté have enabled us to make comparisons with living Central European populations of Calamagrostis stricta. Finally, we thank the editors of Candollea and two anonymous reviewers for their comments and support.
© CONSERVATOIRE ET JARDIN BOTANIQUES DE GENÈVE 2023
