Cortaderia egmontiana (Roem. & Schult.) M.Lyle ex Connor, Darwiniana 49: 90. 2011.

Testoni, Daniel & Linder, H. Peter, 2017, Synoptic taxonomy of Cortaderia Stapf (Danthonioideae, Poaceae), PhytoKeys 76, pp. 39-69 : 53

5. Cortaderia egmontiana (Roem. & Schult.) M.Lyle ex Connor, Darwiniana 49: 90. 2011. Figs 1E , 2E , 3A

Arundo egmontiana Roem. & Schult., Syst. Veg., ed. 15 b [Roemer & Schultes] 2: 511. 1817. Phragmites egmontiana (Roem. & Schult.) Trin. ex Steud., Nomen. Bot. (ed. 2) 2: 324. 1840. Type: Falkland / Malvinas Islands, Port Egmont, R. J. Schuttleworth s.n. (type: BM photo!).

Arundo pilosa d’Urv., Mém. Soc. Linn. Paris 4: 603. 1826; Cortaderia pilosa ( d’Urv.) Hack. ex Dusén, Bol. Acad. Nac. Ci. 16: 253. 1900; Gynerium pilosum ( d’Urv.) Macloskie in Scott, Rep. Princeton Univ. Exped. Patagonia, Botany 8, part 1: 213. 1904; Phragmites pilosa ( d’Urv.) Macloskie & Dusén in Scott, Rep. Princeton Univ. Exped. Patagonia, Botany 8, suppl. bot.: 50. 1915. Ampelodesmos australis Brongn. in Duperrey, Voy. Monde 2(2): 31. 1829, nom. illeg. Type: Falkland / Malvinas Islands, 1825, J. S. C. D. D’Urville s.n. (central inflorescence designated as lectotype by Connor & Edgar, Taxon 23: 600 (1974): P 00740221! (http://mediaphoto.mnhn.fr/media/1443644100310dGB3ZqFqm8JGPDaz; isolectotype: B!).

Calamagrostis patula Steud., Syn. Pl. Glumac. 1(6): 422. 1854. Type: Chile, Huiti, sine data, W. Lechler 760 (lectotype, selected here: P-00740220 (http://mediaphoto.mnhn.fr/media/1443644088798jsLY8AS29Euj4oHx); isolectotypes: GOET; W photo!)

Poa phragmites Phil., Anales Univ. Chile 43: 576. 1873. Type: Chile, volcan de Osorno, 1872, C. Juliet s.n. (holotype: SGO photo! (http://plants.jstor.org/stable/viewer/10.5555/al.ap.specimen.sgo000000667; isotype: BAA! frag. ex SGO);

Gynerium nanum Phil., Anales Univ. Chile 94: 155. 1896. Type: Falkland / Malvinas Islands, Dec. 1884, C. Martin s.n. (lectotype, designated as holotype by Connor & Edgar, Taxon 23: 600 (1974): SGO 065328!; isolectotype: BAA!).

Calamagrostis scirpiformis Phil., Anales Univ. Chile 94: 20. 1896. Type: Chile, ad lacum Llanquihue, I-1866, F. Philippi s.n. (lectotype, designated here: SGO 37097; isolectotypes: US, BAA!)

Cortaderia minima Conert, Syst. Anat. Arundineae 119. 1961; Cortaderia pilosa var. minima (Conert) Nicora, Darwiniana 18(1-2): 80. 1973. Type: Chile, Andes, Villarrica, "in feuchten Schluchten nahe der Waldgrenze", 1897, F. W. Neger s.n. (lectotype, designated as holotype by Conert, Syst. Anat. Arundineae 119 (1961): M; isolectotypes: W5945! B! fragm. ex M).

Etymology.

egmontiana: called after Port Egmont in the Falklands / Malvinas Islands.

Nomenclatural comments.

Brongniart (1829) described Ampelodesmos australis , and explicitly included Arundo pilosa D’Urville as a synonym, noting that this species is better placed in Ampelodesmos .

Taxonomy.

The species can be readily diagnosed by the combination of compact inflorescences, almost glabrous leaves, and either no, or poorly developed, awns and setae on the lemmas. The habit and dense inflorescences are as in Cortaderia sericantha , but Cortaderia egmontiana differs by the absence of setae, and by the almost completely glabrous leaves. The lemma and spikelet morphology (reduced or absent awns and setae) suggests an affinity to the eastern Brazilian species Cortaderia vaginata and Cortaderia modesta . From these two species Cortaderia egmontiana can be separated by the compact inflorescences and the tendency of the leaf blades to disarticulate from the sheaths. It is the only Cortaderia species in southern South American temperate zone. The leaf anatomy (Figs 2E , 3A ) does not show any distinctive peculiarities.

There is remarkable intraspecific variation in the spikelet and floret sizes, and Conert (1961) separated the forms with smaller spikelets as Cortaderia minima . Moore (1983) suggested that the two taxa were latitudinally separated, with the southern populations constituting Cortaderia pilosa , and the northern Cortaderia minima . On the available material, there is indeed a break in the glume length variation. However, this fits no ecological or geographical pattern, and both small and large-glume forms occur in both the Falkland / Malvinas islands and Tierra del Fuego. Further north, indeed, only the small-glume form is found. This suggests that this size variation has no biological significance, accordingly it is ignored here.

Figures

Figure 1. Lemmas of selected species of Cortaderia. A Cortaderia selloana, Juergens 40 (B) B Cortaderia araucana, Borchers s. n. (US) C Cortaderia speciosa, P. M. Peterson 12766 (US) D Cortaderia vaginata, L. B. Smith, P. R. Reitz & R. Klein 7761 (B) E Cortaderia egmontiana, P. M. Peterson, R. J. Soreng & N. Refulio-Rodriguez 17508 (US) F Cortaderia modesta, A. Chase 8288 (US) G Cortaderia hieronymi, A. Burkart et al. 30395 (P) - note that awn and setae are much longer than illustrated H Cortaderia nitida, S. Laegaard 52786 (K) I Cortaderia sericantha, E. Asplund 17175 (B) J Cortaderia bifida, D. N. Smith & J. Cabanillas 7167 (US) K Cortaderia hapalotricha, J. C. Solomon & R. Chevalier 16620 L Cortaderia columbiana, J. P. Schulz 318 (US). All at same magnification.

Figure 2. Leaf anatomy of Cortaderia, as evident from transverse sections. A-B Cortaderia selloana (Villamil 11738) C Cortaderia speciosa (Testoni 644) D Cortaderia vaginata (Zanin 1654). Comparison of bulliform cells in Egmontiana group: E Cortaderia egmontiana (Testoni 634) F Cortaderia modesta (Carauta 927) G Cortaderia vaginata (Zanin 1654). Structures referred to in the descriptions are labelled as follows: 1, multi-layered abaxial sub-epidermal collenchyma layer; 2, aerenchyma; 3, chlorenchyma; 4, primary vascular bundle; 5, midrib; 6, colourless cells; 7, empty cells; 8, bulliform cells.

Figure 3. Leaf anatomy of Cortaderia, as evident from transverse sections. A Cortaderia egmontiana (Moore 2677) B Cortaderia modesta (Glaziou 17913) C Cortaderia hieronymi (Garcia 563) D Cortaderia nitida (Laegaard 53121) E Cortaderia boliviensis (Beck 11273); F Cortaderia sericantha (Ramsay 967); G Cortaderia echinata (Peterson 21587) H Cortaderia bifida (Renvoize 4202) I Cortaderia hapalotricha (Laegaard 53305) J Cortaderia roraimensis (Maguire 60448). Structures referred to in the descriptions are labelled as follows: 1, multi-layered abaxial sub-epidermal collenchyma layer; 2, adaxial islands of collenchyma in the abaxial grooves; 3, chlorenchyma; 4, primary vascular bundle; 5, midrib.