Callitriche antarctica Engelm. ex Hegelmaier (1867: 20)

Lansdown, Richard V. & Hassemer, Gustavo, 2021, The genus Callitriche (Plantaginaceae: Callitricheae) in South America, Phytotaxa 501 (1), pp. 85-118 : 88-92

2. Callitriche antarctica Engelm. ex Hegelmaier (1867: 20)

Type: — FRANCE. ÎLES KERGUELEN: 1839–1843, J.D. Hooker s.n. (lectotype [designated here] MEL barcode MEL2409648! [ Figure 2 ]; isolectotype W QR code W0122126!). Epitype (designated here) : FRANCE. ÎLES KERGUELEN: Grande Terre , Port-aux-Français, elephant seal wallows next to greenhouses, 5 m, 30 December 2011, R.C. Winkworth & F. Hennion 42 (P barcode P02432590! [ Figure 3 ]) .

Description: —Stem and leaf scales present, at least in some populations. Leaf bases broadly connate, forming a cup. Lingulate leaves unknown, lower leaves reduced to scarious spathulate evanescent scales; expanded submerged or floating leaves 2.3–10.0(–18.0) × 1.3–4.8 mm, irregularly 3-veined and sometimes additional free veins from the midrib and side nerves, apical leaves may form a floating rosette, terrestrial leaves somewhat fleshy, similar to expanded leaves but generallY smaller. Flowers solitarY, upper flowers ♂, lower ♀. Bracts lacking. StYle erect, persistent, 1.4–3.2 mm long. Filament short and stout before dehiscence, lengthening to 14 mm long and becoming more delicate after dehiscence; anthers reniform, 0.6–0.7 × 0.7–0.8 mm; pollen yellow. Fruit not strumose, subsessile, as wide as or wider than high, dull brown or blackish when mature, 0.70–1.25 × 0.75–1.50 mm, unwinged.

Illustrations: —plates 1169(11) and 1171(9) in Fassett (1951); Figure 6 in Mason (1959); Figure 6 in Bacigalupo (1979b); Figure 1 (b).

Distribution: —This species occurs on islands from 40º south to Antarctica ( Fassett 1951, Mason 1959, Bacigalupo 1979b, Pisano & Schlatter 1981). It has been recorded in the following locations: Argentina: Tierra del Fuego. Australia: Heard Island, Macquarie Island. Chile: Patagonia ( Domínguez & Aravena 2012). France: Crozet Islands and Possession Island, Kerguelen. New Zealand: Antipodes Island ( Godley 1989), Chatham Island, The Snares ( Hay et al. 2004). South Africa: Prince Edward Islands. UK: Falkland Islands, South Georgia ( van Mieghem & van Oye 1965). Known altitudinal range: 0– 620 m. See map on page 167 in Fassett (1951).

Notes: —In his monograph, Hegelmaier (1867) cited the name as “ C. antarctica in lit.” listing “ C. obtusangula H. monogr.” and “ C. verna J.D. Hook. in sched.” as synonyms. Hegelmaier did not cite a single specimen but listed a number of locations from which specimens were collected during Hooker’s 1839–1843 Antarctic Expedition: “Campbell’s Island; Kerguelen’s Land” and herbaria where these specimens were held: “K. Berl. H. [B herbarium]; K.K.W.H. [W herbarium]; Herb. Sond.; Lenorm. etc.”. The 1839–43 expedition visited the Crozet Islands, Kerguelen Islands, Auckland Islands, Campbell Island, the Falkland Islands and Cockburn Island ( Hooker 1879). Material from Auckland Island must be excluded as this should all be C. aucklandica Mason (1959: 314) . Fassett (1951) provided no clarification of the typification, only citing specimens, as follows: “Campbells [sic.] Island, Hooker (cited by Hooker 1879)”, “Kerguelen’s Land, Hooker, Cotype (MO, GH)”. Mason (1959) noted the apparent confusion over the names C. antarctica , C. obtusangula Le Gall (1852: 202) and C. verna von Linné (1755: 2) (including var. terrestris [Raf.] Torrey [1840: 136]), but listed the following simply as syntypes: “Antarctic Archipelago, J. D. Hooker; Campbell I., J. D. Hooker; Keguelen’s Land, J.D. Hooker”. Schotsman (1961) considered that material from different island groups showed different morphological characters and concluded that they could be divided into three groups: one including Campbell Island, Auckland Island and Île Amsterdam, a second involving material from Cape Horn and a third involving material from Kerguelen’s Land. Her review included type material from Kerguelen’s Land but not from other locations. She concluded that the species referred to as C. antarctica actually involves more than one taxon, but that available information was inadequate to recognise taxonomic divisions. However, given that material from Auckland Island was already considered to be a separate species endemic to the Auckland Island archipelago at the time ( Mason 1959), this grouping must be treated with caution. Measurement of fruit from throughout the range of the species has shown a considerable overlap from all areas and therefore it is best, certainly until further studies of fresh material and probably molecular studies can be made, to consider populations from Campbell Island and the Kerguelen Islands to be conspecific.

Four distinct gatherings are represented in the type material from Kerguelen’s Land at GH (barcode 00048926), the principal label is blue (identical to that at G) and says simply “ Callitriche verna L., Kerguelen’s Land, Cape Horn, Antarct. Exped., 1839–1843, J.D.H [Joseph Dalton Hooker]” annotated “ C. antarctica Engelm. ” on the same label, apparently in the same handwriting. Another label below and presumably referring to the specimen on the top left of the sheet reads “ Callitriche antarctica Engelm. ex Hegelm. , C. obtusangula Hegelm. monogr. ex parti” and is signed G.E [presumably George Engelmann] 1865. A label indicating the top right-hand specimens on the sheet reads “ Callitriche antarctica Engelm. ex Hegelm , co-types” and with the typed name “N.C. Fassett 1949”. This material is a very poor selection as a type for C. antarctica because different collections are represented on the same sheet, the material has no good fruit and the reproductive parts present are becoming degraded. Although any material collected by J.D. Hooker during the Antarctic Expedition of 1839–1843 from Campbell’s Island or the Kerguelen Islands could be taken to comprise original material of C. antarctica , specimens from the Kerguelen Islands have generally been considered to represent the type ( Fassett 1951, Mason 1959, Schotsman 1961). Therefore, we designate the specimen MEL barcode MEL2409648, which is the best specimen among the syntypes from Kerguelen Islands as lectotype of the name C. antarctica . Despite being the best available option among the syntypes, the selected lectotype is in poor condition, with very few mature fruit, which is unfortunate because it could lead to confusion regarding the application of the name C. antarctica should this name be segregated into more species in the future. To ensure the unequivocal application of the name C. antarctica , and in accordance with Art. 9.9 of the Code, we designate here the specimen P barcode P02432590, also from Kerguelen, as epitype; this specimen is in good condition, with good mature fruit.

In general, C. antarctica (as circumscribed here) is easily recognised by the fleshy leaves which are broadly connate, forming a cup around the stem, with the lower leaves reduced to scales, combined with the unwinged fruit. Some herbarium specimens resemble C. heterophylla , but can usually be distinguished by vegetative characters, as well as the extremely robust filament before dehiscence.

Conservation status: — Callitriche antarctica is classed as Least Concern (LC) because it is widespread, at least locally abundant and faces no known significant threats.

Additional material studied: — ARGENTINA. TIERRA DEL FUEGO: I. Soleidad, J. D’Urville 118 (P barcode P03824027); Hermite Island, Cape Horn, J.D. Hooker s.n. (BM, P barcode P03824028, P barcode P03824029); south banks of Lago Fagnano west of Kosobo, area submerged by 1959 earthquake; low pond with dead trees, ground frozen, 16 May 1972, N.P. Goodall 1261 (GH). AUSTRALIA. HEARD AND MACDONALD ISLANDS: Growing in a seepage pool amongst Azorella selago and Poa cookii, Erratic Point , Heard Island, 53º 03’ S, 73º 23’ E, 10 October 1985, J.M.R. Hughes s.n. (HO-577376); slope, slightly undulating, E aspect, peat pockets on basalt moraine, pool complex, with Azorella selago , Poa cookii , Colobanthus kerguelensis , Pringlea antiscorbutica and Acaena , c. 100 m SE of Spit by Station, 53º 06’ 34” S, 73º 43’ 11” E, 10 m, 13 March 1993, S. Donaldson 215 (CANB-9303621); MACQUARIE ISLAND: At edge of seal wallow area, among Poa foliosa tussocks, west side of The Isthmus, 54º 30’ S, 158º 57’ E, 3 m, 9 November 1981, R.D. Seppelt 11893 (HO-67727); on peat at edge of seal wallow, in Poa foliosa tussocks, 54º 30’ S, 158º 57’ E, 19 November 1981, R.D. Seppelt 11892 (HO-67726); amongst Poa foliosa tussocks on wet organically rich soil and litter in seal wallow, west side of The Isthmus, 54º 30’ S, 158º 57’ E, 3 m, 19 November 1981, R.D. Seppelt 11891 (HO-67725); southern shore of Sandy Bay, 5 July 1950, B.W. Taylor s.n. (AD-96643083Z); on bare ground between Poa foliosa tussocks, Hurd Point, 5 December 1959, D.M. Moore & A.B. Costin 11 (CANB- 61302); swamps near West Point, Macquarie Island, s.d., N. Hamilton s.n. (NSW-935583); on muddy bank [beside] and in pool, flat raised platform at foot of steep slope, open aspect, waterlogged peat, herbfield with Pleorphyllum stilbocarpa and Agrostis very common, N end of west coast between Hasselborough west and Handspike Point, Macquarie Island, Tasmania, 5 m, 24 November 1989, J.R. Croft 10404 & P. Selkirk (NSW-539624, HO-306856); on mud and water surface of seal wallows amongst Poa foliosa tussocks, Green Gorge, Macquarie Island, 22 November 1979, P. Selkirk s.n. (NSW-594180); in fibrous peat on coastal slope, Camp Hill, Macquarie Island, 4 February 1951, B.W. Taylor s.n. (NSW-935585); moist peat, tractor Hazzard Bay, 19 February 1951, B.W. Taylor s.n. (MEL 2271173); seal wallow, Isthmus, Macquarie Island, 54º 30’ S, 158º 57’ E, Nov. 1976, P. Tyler s.n. (HO-30836); tussock/bog area near Boiler Rocks, West coast Macquarie Island, 54º 33’ S, 158º 54’ E, 16 December 1980, D. Montgomery and G. Leaman 37 (HO-39210); southern slope of Wireless Hill, Macquarie Island, 54º 30’ S, 158º 57’ E, 31 July 1948, N.R. Laird s.n. (BRI-AQ418853, HO-86411, NSW-935584); some yards from sea, eastern lower slopes of Wireless Hill, Macquarie Island, 54º 30’ S, 158º 57’ E, 18 February 1949, N.R. Laird s.n. (HO-86417); southern slopes of Wireless Hill, Macquarie Island, 54º 30’ S, 158º 58’ E, 7 February 1949, N.R. Laird s.n. (HO-86422); 54º 37’ S, 158º 51’ E, N.R. Laird s.n. (HO-86347); edge of road in Poa foliosa association, near Biology Laboratory, The Isthmus, Macquarie Island, 25 November 1894, R.D. Seppelt 14781 (HO-577381); on sand among Poa foliosa at edge of seal wallow, The Isthmus, 40 m W of Biology Laboratory, Macquarie Island, 54º 30’ S, 158º 56’ E, 5 m, 2 November 1984, R.D. Seppelt 14665 (HO-577386); at edge of Poa foliosa stand, The Isthmus, W side of Biology Laboratory, 54º 30’ S, 158º 56’ E, 5 m, 23 January 1935, R.D. Seppelt 15268 (HO-577387); at edge of path on coarse sandy peat, Garden Cove, 54º 30’ S, 158º 57’ E, s.d., R.D. Seppelt 14988 (CHR-553808). CHILE. MAGALLANES: Istmo de Ofqui, 1921, P. Gusinde & C.M. Hicken s.n. (SI); forma céspedes denses sobre barre en sitios sombríes, pinguinera en peninsula S.E., Isla Hornos, Arch. Cabo de Hornos, 17 November 1981, E. Pisane V. 5261 (GH). FRANCE. ILE AMSTERDAM: Sur la mousse humide, a 620 m, 24 December 1874, G. de L’Isle 32 (K). KERGUELEN’S LAND: J.H. Kidder s.n. (G, NY); wet places near the sea, generally in company with Ranunculus crassipes , 22 December 1872, J.H. Kidder 255 (PH-229182). NEW ZEALAND. CAMPBELL ISLAND: Around elephant seal wallows, Look-out Bay, Perserverance Harbour, 13 January 1947, W.B. Brockie s.n. (AD-98138284); Campbell Islands, 29 March 1949, E.H. Walker 5070a ( US); Tucker Cove, Campbell Island, 2 March 1946, J.H. SØrensen s.n. (AD-97637035, CANB-329948, CHR-251984, NSW-935587); common about old sea elephant wallows, also along tracks, Tucker Cove, Campbell Island, 25 January 1961, V.D. Zotov 113548 (AD-98503333, CANB-351715); slopes of Mount Honey, 12 November 1944, R.L. Oliver s.n. (CHR-251985); in freshwater trickles on maritime rocks, near Tucker Point, J.F. Findlay s.n. (CHR-251988); Campbell Island, 1943, J.H. SØrensen s.n. (CHR-251987); with Poa litorosa , Bulbinella rossii , Polystichum vestitum , freshwater seep among tussocks, Tucker Cove, 52º 32.864’ S, 169º 08.52’ E, 4 m, 20 December 2010, S.J. Wagstaff 45 (CHR-624345). SOUTH AFRICA. PRINCE EDWARD ISLANDS: Disused Elephant seal wallows near Paddy Rocks, Transvaal Cove, Marion Island, 12 December 1965, B.J. Huntley 959 (K, MEL-1520139). UNITED KINGDOM. FALKLAND ISLANDS: Moist sandy soil by runnel into sea, with Plantago barbata, Ten Shilling Bay Peninsula, W. coast, c. 1½ miles SE Calm Head, Port Stephens, West Falkland, 2 February 1964, D.M. Moore 753 (C, K, US); in ditch next to southern pond, Motley Island, Falkland Islands, 52.1388º S,-58.6019º, 3 February 2009, W.R. Upson RU86 (K barcode K000649869). SOUTH GEORGIA: Stony ground by waterfall, inner beach, N.E. of Ducloz Head, Undine South, 10 ft., 10 March 1961, S.W. Greene 2581 (K barcode K000368855, P); at edge of pools in tussock behind beach, inner beach near the snout of the Esmark Glacier, Holmestrand, ca. 10 ft., 11 March 1961, S.W. Greene 2585 (GH, K barcode K000368845, P); on edge of tussock stool by pool, behind beach at head of Motke Harbour, Royal Bay, ca. 10 ft., 19 February 1961, S.W. Greene 2309 (K barcode K000368843); at edge of pools in tussock behind beach, inner beach near the snout of the Esmarck Glacier, Holmestrand, 10 ft., 11 March 1961, S.W. Greene 2585 (K); on edge of tussock stool by pool, behind beach at head of Moltke Harbour, Royal Bay, 10 ft., 19 February 1961, S.W. Greene 2309 (GH); amongst tussock behind shore, Johan Harbour, 10 ft., 23 January 1961, S.W. Greene 1175 & N.V. Jones (MEL-290908); on damp peat at edge of stream through tussock, by southern corner of Brunonia Glacier, Sunset Fjord, Bay of Isles, 22 January 1961, S.W. Greene 1174 (P); creeping herb, small patches to 20 cm diameter, hard mossbank, mossy area in Festuca-fellfield mosaic, Cobblers Cove,-54º.2’74” S,-36º.3’04” W (WGS 1984), 170 m, 22 January 2009, J. Osborne et al. 558 (K barcode K000650254); tussock and Acaena , in damp patches with moss, liverwort and Acaena, Cap Rosa ,-54º.1’87” S,-37º.4’07” W (WGS 1984), 45 m, 2 January 2009, M. Briggs et al. 202 (K barcode K000650255).

Figures

FIGURE 1. Fruits of South American Callitriche: a—C. albomarginata, b—C. antarctica, c—C. berteroana, d—C. ciliata, e—C. ciliata showing fibrils, f—C. concinna, g—C. dacryoidea, h—C. deflexa, i—C. ecarinata, j—C. hegelmaieriana, k—C. heterophylla, l—C. heteropoda.

FIGURE 2. Lectotype of Callitriche antarctica (J.D. Hooker s.n., MEL barcode MEL2409648). Copyright: Royal Botanic Gardens Victoria.

FIGURE 3. Epitype of Callitriche antarctica (R.C. Winkworth & F. Hennion 42, P barcode P02432590). Copyright: Muséum National d’Histoire Naturelle.

FIGURE 6. Holotype of Callitriche mandonis (G. Mandon 1456, BR barcode AWH12906680). Copyright: Plantentuin Meise.