Callitriche mandonis van Heurck & Müller (1871: 136–137)

Lansdown, Richard V. & Hassemer, Gustavo, 2021, The genus Callitriche (Plantaginaceae: Callitricheae) in South America, Phytotaxa 501 (1), pp. 85-118 : 104

13. Callitriche mandonis van Heurck & Müller (1871: 136–137)

Type: — BOLIVIA. LA PAZ: In lagunal de [..], Provincia Larecaja-viciniis Sorata , Gualatun apachetai, alt. rivules keg. Alpinal, 4000–4100 m, 9 March 1860, G. Mandon 1456 (holotype BR barcode AWH12906680! [ Figure 6 ]; isotypes BM!, G!, GH barcode 00048931!, K barcode K000471001!, NY barcode 00248744!, P barcode P04214850!, P barcode P03986063!, P barcode P04214911!) .

Description: —Stem and leaf scales present. Leaf bases connate. Lingulate leaves 10–12 mm × 1 mm, expanded submerged or floating leaves spathulate, elliptic, 2.3–8.0 × 1.0–4.0 mm, petiole 1.1–3.2 mm, venation simple, occasionally tertiary loops outside the secondary veins, the apical leaves forming a floating rosette, leaves of terrestrial plants unknown. 1 ♂ and 1♀ flower in one of a pair of aXils, opposed bY a ♀. Bracts persistent, 1.3 mm long. StYle erect to slightlY spreading, ≤ 4.1 mm long. Filament erect, ≤ 5.3 mm long, anther 0.4 × 0.3 mm, pollen Yellow. Fruit not strumose, subsessile, more or less as wide as long, blackish when mature contrasting with paler wing, 1.0–1.5 × 0.9–1.4 mm, wing at apex and down the upper part of sides but base unwinged.

Illustrations: — Figure 5 (b).

Distribution: — Callitriche mandonis has been recorded from Bolivia (La Paz), Ecuador (Azuay, Pinchincha, Napo) and Peru (Cajamarca, La Libertad, Puno), however it is likely to be under-recorded and its distribution may well be much wider. Known altitudinal range: 2685–4050 m.

Notes: — Callitriche mandonis has generally been overlooked within C. rimosa from which it can be distinguished by the wing of the fruit which extends from the top, partly down the sides but not to the base unlike C. rimosa which is characterised by the wing extending into the commissurial groove. The winged apex but unwinged base to the fruit is unique to this species among Callitriche species recorded from South America.

Conservation status: — Callitriche mandonis is classed as Least Concern (LC) because it has a fairly wide distribution and there are specimens collected as recently as 1997.

Additional material studied: — BOLIVIA. LA PAZ: Forming mats in shallow water, small bog surrounded by low cloud forest with Myrica , Brunellia, Weinnmannia etc., entire area more or less disturbed, Prov. Nor Yungas, Cotoata (46.9 km from puesto de transito Chuquiaguillo), 16.18’S, 67.51’W, 3200 m, 11 February 1983, J.C. Solomon 9484 (K); Challapampa, Murillo Province, ca. 3800 m, 26 October 1920, E. Asplund 588 (NY); Yungas, 1887, M. Bang (F, G barcode G00414935, G barcode G00414941, GH, NY, PH). ECUADOR. AZUAY: Ditch, secondary cloud forest and mountain scrub along road, about 5 km NW of Sayaus on road to Cajas, 79º 07’ W, 2º 50’ S, 3000 m, 15 June 1979, B. LØjtnant et al. 14847 (NY); PINCHINCHA: On margin of stream near Hacienda Antisana, Cerro Antisana, 4050 m, 8 August 1960, P.J. Grubb et al. 701 (K, NY); NAPO: In small streams in pasture, montane forest with grazed pasture in clearings, W of the lake, road Quito-Baez, at Laguna de Papallacta, 78 06” W, 0 21” S, 17 July 1976, B. Øllgaard & H. Balslev 8015 (NY). PERU. CAJAMARCA: Flotante pero enrraizada en el fango, Pajonal de jalca, al costado de un curso de agua, suelo turboso, humedo, entre Coymolache y el desvio de la carretera a Llapa, sobre la carretera Cajamarca Hualgayoc, 3000 m, 8 August 1981, I. Sánchez Vega et al. 2685 (F); parte baja del Cerro Shillas negras y Laguna Totora, 3920 m, 2 April 1994, I. Sanchez Vega & M. Cabanillas S. 7005 (F); LA LIBERTAD: Flotante en pozo de quebrada, arriba del pueblo de Shulgón, Otuzco Province, 3540 m, 4 June 1992, S. Leiva & P. Leiva 509 (F, NY); PUNO: Spring-fed ditch at hacienda, ½ km SE of Hac. Santa Rosa de Achaco, 9 January 1963, H.H. Iltis & D. Ugent 1330 ( US); small cold clear stream (with Myriophyllum , Elodea , Callitriche , Limosella , Zannichellia , Potamogeton spp. and Lilaea subulata ), at road and rail crossing of stream draining Lago Jaracocha, ca. 9 km SW of Santa Lucia, Lampa Province, 4000 m, 12 January 1963, H.H. Iltis et al. 1447 ( US); Locally frequent in shallow (10–20 cm deep) ditches by a track, steep-sided valley with bare rocky slopes covered in rough grassland and with lakes in valley bottom, Murillo, Zongo valley, 3600 m, 28 June 1997, J.R.I. Wood 12357 (K).

Figures

FIGURE 5. Fruits of South American Callitriche: a—C. lechleri, b—C. mandonis, c—C. nubigena, d—C. oblongicarpa, e—C. praetermissa, f—C. quindiensis, g—C. rimosa, h—C. schotsmaniana, i—C. stagnalis, j—C. terrestris, k—C. turfosa.

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