Callitriche heteropoda Engelm. ex Hegelmaier (1867: 40)

Lansdown, Richard V. & Hassemer, Gustavo, 2021, The genus Callitriche (Plantaginaceae: Callitricheae) in South America, Phytotaxa 501 (1), pp. 85-118 : 101

11. Callitriche heteropoda Engelm. ex Hegelmaier (1867: 40)

Type: — BOLIVIA. LA PAZ: Viciniis Sorata ; Gualata, apacheta des Sajena de Chucha, de [illegible], Prov. Larecaja, in lacunis rivulis, reg. alpina 4000–4100 m, 1859 March 1860, G. Mandon 1456 (lectotype [designated here] BR barcode BR000000696929! [two lower plants on sheet] [ Figure 4 ]; isolectotypes BM!, G!, GH barcode 110079795!, K barcode K000471001!, MO-1913772, MO-1913773, MO-1913774, NY barcode 00248744!, P barcode P04214850!, P barcode P04214911!) .

Description: —Stem and leaf scales present. Leaf bases connate. Lingulate leaves 0.6 × 5.0– 5.5 mm, expanded submerged or floating leaves broadly ovate, 2.3–4.9 × 1.3–3.4 mm, petiole 1.6–4.7, 3-veined, occasionally with an additional loop on one of the secondary veins, apical leaves forming a floating rosette, leaves of terrestrial plants unknown. Bracts caducous, 0.6–1.0 mm. StYle erect, persistent, ≤ 2.6 mm. Filament erect, ≤ 5.5 mm; anther reniform, 0.4–0.5 mm diameter; pollen yellow. Fruit not strumose, subsessile, as high as or higher than wide, grey-brown to maroon when mature, 1.1–1.3 × 1.0– 1.2 mm, unwinged.

Illustrations: —plate 1173(12) in Fassett (1951); Figure 3 (j–l) in Bacigalupo (1979b); Figure 1 (l).

Distribution: —This species occurs in Venezuela (Mérida), Peru (Ancash, Cuzco and Puno), in Ecuador (Azuay, Cañar, Chimborazo, Imbabura, Napo, Pichincha, and Tungurahua), Argentina (Córdoba) and the type locality near Sorata in Larecaja Province, La Paz, Bolivia ( MacBride 1951, de la Barra 2003). Known altitudinal range: 3400–4360 m. See map on page 173 in Fassett (1951).

Notes: —The gathering G. Mandon 1456 was listed by Fassett (1951: 172) under Callitriche heteropoda as “type in MO, isotypes in MO, GH, NY; however it is also listed in the description of C. mandonis as “G. Mandon 1456 (in Herb. Van Heurck”) ( van Heurck and Müller 1871: 136). The various elements of this gathering in different herbaria (BM, BR barcode BR000000696929!, G, GH barcode 110079795, K barcode K000471001, MO-1913772, MO-1913773, MO-1913774, NY barcode 00248744, P barcode P04214850, P barcode P04214911) represent different combinations of C. heteropoda and C. mandonis , including sheets with only one species and sheets with both species. No original specimen for C. heteropoda could be located at STU (Mike Thiv, pers. comm., 27 October 2020). There is a single specimen (BR barcode AWH12906680) from the gathering G. Mandon 1456 in van Heurck’s herbarium; however, this specimen is entirely C. mandonis q.v. All other elements of G. Mandon 1456 seen involve mixed collections, except a sheet in the Bullemont Herbarium at BR. This sheet has five specimens, two of which on the upper part of the sheet are C. mandonis , one has only immature fruit and cannot reliably be determined and the lower two are C. heteropoda . The two lower specimens on sheet BR barcode BR000000696929 have therefore been selected and designated here as the lectotype of C. heteropoda .

Callitriche oblongicarpa has been mistaken for this species, hence the statement “or on peduncles up to 15 mm ” ( Bacigalupo 1979b) however confirmed C. heteropoda only has sessile fruit. It can be distinguished from all other Callitriche species by the fruit which are unwinged and of more or less even width from base to apex, resembling that of C. obtusangula but differing from that species in the bracts, stigma length and filament length (e.g. Lansdown 2008).

Conservation status: — Callitriche heteropoda has a wide range and there are numerous relatively recent records, it is therefore classed as Least Concern (LC).

Additional material studied: — ARGENTINA. CÓRDOBA: Hieronymous 537 (CORD); Tucumán: Sparre 8586 (LIL). BOLIVIA. COCHABAMBA: In 30–40 cm water, in bog pool (probably seasonal) in a hollow in open moorland, on the summit/junction on road from Qillacollo to Morochata, Cordillera Tunari, 4300 m, 28 January 1995, J.R.I. Wood 9231 (K); LA PAZ: Flaques d’eau, La Lancha, Ravin de Chuquiaguillo, 1851, M. Weddell s.n. (P barcode P05027489); Pacocoha Pampa, Valle de Chuiaquillo, Province Murillo, 4280 m, 7 April 1921, E. Asplund 3441 (NY); flotanto en el agua pero con las raices hundidas en el cieno del fondo, cecra de Achacachi en un area inundada con gramineas, Omasuyos, 4100 m, 8 March 1982 F.J.F. Casas 6617 & J. Molero (G, HUA, NY); dans petite mare, Valle de Zongo, 6 km avant la Cumbre, 4100 m, 24 April 1988, A. Fournet & P. Caballion 808 (US); riachuelo con poca corriente cerca del pueblo, Ulla-Ulla, Prov. F. Tamayo, 4360 m, 18 April 1982, X. Menhofer 1086 (SI). PERU. CUZCO: En laguna, pajonal bajo de quemado, Parque Nacional Manu, Cerro Macho Cruz, Acjanaco, Paucartambo Province, 3400–3450 m., 2 March 1991, A. Cano E. 4454 (F); pool in Distichia moor, La Raya, Cusco Department, 22 April 1925, F.W. Pennell 13493 (F, GH, PH). VENEZUELA. MÉRIDA: Páramo de Mucuchies, [illegible], 4100–4300 m, 20 November 1976, A. Ghanpiu et al. 13626 (G).

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

FIGURE 4. Lectotype of Callitriche heteropoda (G. Mandon 1456, BR barcode BR000000696929). Copyright: Plantentuin Meise.