Callitriche berteroana (Hegelm.) Lansdown & Hassemer

Lansdown, Richard V. & Hassemer, Gustavo, 2021, The genus Callitriche (Plantaginaceae: Callitricheae) in South America, Phytotaxa 501 (1), pp. 85-118 : 93

3. Callitriche berteroana (Hegelm.) Lansdown & Hassemer , comb. & stat. nov.

≡ Callitriche marginata var. berteroana Hegelmaier (1867: 12) .

≡ Callitriche lechleri var. berteroana (Hegelm.) Fassett (1951: 192) .

Type: — CHILE. O’HIGGINS: Mont [Cerro] la Leona, August 1828, C.L.G. Bertero 141 (holotype P barcode P00697226!; isotypes G!, GH barcode 00048934!, MO-1913780!, P barcode P00697227!) .

— Callitriche berteroniana von Steudel (1840: 259) , nom. inval. (Arts. 38.1 and 38.3 of the Code).

Description: —Stem and leaf scales present. Leaf bases connate. Lingulate leaves unknown, expanded submerged or floating leaves narrowly elliptic, 2.3–5.6 × 1.7–2.9, petiole 1.3–3.5, venation usually simple, 3–5 veins, the tertiary veins sometimes anastomosing, the apical leaves forming a floating rosette, leaves of terrestrial plants unknown. Flowers solitarY. Bracts persistent, ♀ 0.4–0.7 mm long, ♂ 0.6 mm long. StYles erect, <2.3 mm long. Filament, erect <2.4 mm long; anther 0.2–0.3 × 0.3–0.4 mm; pollen Yellow. Fruit not strumose, subsessile or on pedicel to 6.2 mm long, wider than or occasionally as wide as high, pale brown or rich brown contrasting with paler wing when mature, 0.8–1.3 × 0.9–1.4 mm, wing 0.5 mm wide all around, very even width.

Illustrations: —plate 1174(18c–m) in Fassett (1951); Figure 1 (c).

Distribution: — Callitriche berteroana is endemic to Araucanía and Valparaíso Provinces in Chile, with a single record from the Juan Fernández Islands. Known altitudinal range: 1200 m. See map on page 193 in Fassett (1951).

Notes: —The earliest appearance of this entity was in von Steudel (1840), as Callitriche berteroniana ; however, this name was not validly published because it lacked a diagnosis and a description (Arts. 38.1 and 38.3 of the Code). Von Steudel did, however, provide information on a gathering (“ Chili ” and “ Bert. hrb. nr. 141”), which was later the basis for the first validly published name for this entity: C. marginata var. berteroana , by Hegelmaier (1867) who provided the following information on the type: “ C. autumnalis Bert. in sched. C. Berteroiana Steud. Herb. (et Nomencl.)” and “ β kommt in Chile vor („in spongiosis humidis mont. La Leona 1828, Oct. fl. et fr.” Herb. Steud.)”. Hegelmaier therefore made an unequivocal reference to von Steudel’s name. The holotype was located at P (barcode P00697226). We should remark that Fassett (1951: 192) transferred this entity to the infraspecific sphere of C. lechleri (Hegelm.) Fassett (1951: 191–194 , t. 1174[18]), and listed isotypes (“ Bertero 141 (ISOTYPE of C. Berteroiana Steud.— GH, MO)”).

Callitriche berteroana differs from all other Callitriche species in South America by its combination of fruit which are broader than long and broadlY winged throughout, some fruit on all specimens with pedicels <6.2 mm long, combined with the presence of stem and leaf scales. It most closely resembles C. marginata Torrey (1856: 135) , from which it differs in the fruit which are longer, from C. lechleri in the consistently broader wing on the fruit and from both in the capacity to develop longer pedicels. It also resembles C. brutia var. naftolskyi (Warb. & Eig) Lansdown et al. (2017a: 92) , from which it differs in the broader wing of the fruit and yellow pollen. These differences are sufficient to justify its treatment as a separate species.

Conservation status: —Available information is inadequate to derive an informed assessment of the conservation status of this species and it is therefore classed as Data Deficient (DD).

Additional material studied: — CHILE.ad portum Coronel: Car . Ochsenius, communic.Buchenau1866 [collected by Carl-Christian Ochsenius, communicated by Buchenau to Martius in 1866] (BR barcode BR0000024932936) [note by Hegelmaier: “forma ad C. berteroanam Steud. accedens, inter hanc et C. lechleri (quas duas C. marginatae Torr. subjugendas censui) ambigua.—Fructus pro parte pedunculati! Hegelmaier.”]. ARAUCANÍA: Heavy sod, creek bank, meadow and forest, with small creek and swamp area adjacent to meadow, near southern boundary, Fundo Solano, Los Alpes, Cordillera de Nahuelbuta, Province Malleco, 1200 m, 18 January 1958, W.J. Eyerdam 10258B (F); submersed in quiet pools, meadow and forest with small creek and swamp area adjacent to meadow, near southern boundary Fundo Solano, Los Alpes, Cordillera de Nahuelbuta, Malleco Province, 18 January 1958, W.J. Eyerdam 10342 (F, US). VALPARAÍSO: Valle de Marga-Marga, Aconcagua Province (coast ranges south-easterly from Valparaíso ca. lat. 33º 10’ S), F. Jaffuel & A. Pirion 3208 (GH [paratype]); Quillota, collector unknown (G); aquatic in a spring flowing from base of a steep bank, edge of the settlement of San Juan Bautista, toward Pangal, Cumberland Bay, Juan Fernandez Islands, 21 December 1965, F.G. Meyer 9629 (K).

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.