Oxybasis frigida (Phil.) Uotila, 2022

Uotila, Pertti, 2022, New combinations and notes on Oxybasis (Amaranthaceae) from southern South America, Candollea 77 (1), pp. 9-16 : 10-12

Oxybasis frigida (Phil.) Uotila , comb. nov.

 Chenopodium frigidum Phil., Fl. Atacam. : 47. 1860.

Holot y pus: C H I L E. Reg. Antofag asta: R i o f r i o in deserto Atacamensi, II.1854, R.A. Philippi s.n. (SGO [SGO000001632] image!; iso-: G [G00412681 fragm.]!). Fig. 1 .

Distribution and ecology. – Oxybasis frigida grows at high elevations (2500–4200 m) of the Andes of Chile (regions of Tarapacá, Antofagasta, Atacama, Coquimbo, Metropolitan) and Argentina (provinces of Catamarca, La Rioja, San Juan, Mendoza, Neuquén) (MÚLGURA & MARTICORENA, 2008; BRIGNONE, 2020).

Notes. – Differences between terminal and lateral flowers and their seed position are important diagnostic characters for distinguishing Oxybasis from the other genera of the former Chenopodium s.l. and such features support the transfer of C. frigidum Phil. to Oxybasis . Its growth habit and the leaf shape and thickness also correspond well to Oxybasis . A dense indumentum composed of vesicular hairs on the lower leaf surface is typical for several Oxybasis species, e.g., O. glauca (L.) S. Fuentes et al. and O. macrosperma subsp. salsa (Phil.) Uotila [new combination below], but a dense cover of vesicular hairs on both leaf surfaces is unknown for the other species of Oxybasis , which broadens the original description of the genus. Dense indumentum and presence of small bracts may be adaptations to a harsh, cold environment.

An isotype of Chenopodium frigidum was kept at W, but it was destroyed during the Second World War. However, Aellen took a fragment from it before the War as recorded by himself: “ Chenopodium frigidum Phil. (Original exempl.), Chili; Desert. Atacama, Riofrio (l.cl.), leg. Philippi ”. The fragment is small but shows the essential characters concerning the leaves, flowers and seeds ( Fig. 1 ) .

The original material of Chenopodium hypsophilum Hauman has not been studied. However, and according to AELLEN (1929), it is most probably a later heterotypic synonym of C. frigidum .

Additional specimens examined. – CHILE. Reg. Atacama: Wüste Atacama, in Vega Ancha , 20 km E vom Salar de Pedernales , 3600 m, 16. I .1966, Zöllner 1103 ( G). Reg. Coquimbo: Illapel, Cerro La Yerba Loca, 3450 m, 21.XII.1938, Morrison 16981 ( K). Reg. Tarapacá: Parinacota 42.7 km E of Pica , 20°21'58"S 69°24'00"W, 3741 m, 17. V .2005, Acosta et al. INIA. BB 382 ( K) .

ARGENTINA. Prov. Mendoza: Las Heras ( Estancia San Isidro ), Agua de los Pajaritos , 2600 m, 14. I .1964, Ruiz Leal 23126 ( G); San Carlos , Quebrada del Paso de la Cruz de Piedra , 16. I .1949 , Ruiz Leal 11771 ( G). Prov. San Juan: Calingasta , Reserva Natural Estricta El Leoncito, Quebrada Vaquita Muerta, 25. I .1995 , Apochian et al. 227 ( K); Arroyo Tambillos, along trail from Paso de Valeriano , Pueblo Tambillo, 29°10'S 69°51'W, c. 4000 m, 10. I .1926, Johnston 6100 ( K) .

Figures

Fig. 1. – Isotype of Chenopodium frigidum Phil. ( Oxybasis frigida (Phil.) Uotila) originating from the Aellen herbarium in G. [G00412681;Conservatoire et Jardin botaniques de Genève]