Nasa humboldtiana (Urb. & Gilg) Weigend subsp. humboldtiana

Henning, Tilo, Acuna-Castillo, Rafael, Cornejo, Xavier, Gonzales, Paul, Segovia, Edgar, Wong Sato, Akira Armando & Weigend, Maximilian, 2023, When the absence of evidence is not the evidence of absence: Nasa (Loasaceae) rediscoveries from Peru and Ecuador, and the contribution of community science networks, PhytoKeys 229, pp. 1-19 : 1

Nasa humboldtiana (Urb. & Gilg) Weigend subsp. humboldtiana

Fig. 2A, B

Loasa humboldtiana Urg. & Gilg, Nova Acta Acad. Caes. Leop.-Carol. German. Nat. Cur. 76: 240, pl. 5, fig. 40 (1900). Type. Ecuador. Chimborazo: Cantón Chunchi?, in andibus ecuadorensibus, Llalla, Aug 1859, R. Spruce 6002 (lectotype, designated in Weigend 1996a: 232: P! [00123885]; isolectotypes: B[destroyed, F Neg No. 10196!], BM! [BM000021453], E! [E00085319], F! [acc. #1540659], GH! [00076022], GOET!, K! [K000372786, K000372787, K000372788], M! [0113254], OXF!, P [P02273159] S! [acc. # S-R-8215], W! [0053328, 1889-0113217]).

Type.

Based on Loasa humboldtiana Urb. & Gilg.

Nasa humboldtiana belongs to the Nasa triphylla (Juss.) Weigend complex ( Dostert and Weigend 1999), a natural group of herbaceous annuals found in the undergrowth of humid forest and disturbed sites in the northern Andes and Central America. This group is characterized by compound leaves (Fig. 2A ), a trait that is very rare in Nasa ( Acuña-Castillo et al. 2021). The highest number of species in this complex is in the AHZ, only two out of 24 taxa (including subspecies) grow exclusively outside this region ( Dostert and Weigend 1999).

Nasa (Loasa) humboldtiana has been very poorly understood since its original description, with only two known collections from the 19th century ( Weigend 1996a). In recent years, extensive field studies yielded several new taxa closely allied to Nasa humboldtiana . In a synopsis of the Nasa triphylla complex ( Dostert and Weigend 1999), N. humboldtiana was expanded to include three additional infraspecific taxa namely subsp. Nasa humboldtiana roseoalba (Weigend) Dostert (originally described as a distinct species, Loasa roseoalba Weigend: Weigend 1996a), subsp. Nasa roseoalba tricolor Dostert & Weigend and subsp. Nasa roseoalba obliqua Dostert & Weigend. Later, targeted field work led to the discovery of two additional subspecies. Nasa humboldtiana subsp. subtrifoliata Weigend & T.Henning and subsp. glandulifera Weigend & T.Henning are endemic to small forest remnants in northern Peru and under imminent threat of extinction ( Henning and Weigend 2009).

Nasa (Loasa) humboldtiana was described in 1900 ( Urban and Gilg 1900), and the most recent herbarium collection by Richard Spruce dated back to Aug. 1859 from what today is the southern part of the province of Chimborazo, Ecuador ( Spruce 1908 p. 222 & 249-250). Nasa humboldtiana subsp. humboldtiana differs most notably from the other subspecies by its remarkably different nectar scales, with a rectangular (instead of tapering) scale neck ( Henning and Weigend 2009). In 2021, one of us (XC) collected material clearly referable to the typical subspecies Nasa humboldtiana humboldtiana in a ravine within a conserved remnant of montane Andean forest in El Corazón, a private property located in the province of Chimborazo (Fig. 2A, B ), ca. 30 km straight line from the type locality of this taxon, which signifies the rediscovery of the taxon after 162 years. The same population, represented by fewer than five individuals, has been observed in the field flowering at least twice (XC), most recently in August 2022 .

Additional specimens examined.

Ecuador. Chimborazo: Cantón Pallatanga, Reserva El Corazón, a montane Andean forest , ca. 2700 m, 2°3'S, 78°54'W, 10 Jul 2021, X. Cornejo & J. Josse 9388 (GUAY) .

Figures

Figure 2. A-D Nasa humboldtiana E, F Nasa ramirezii G, H Nasa solaria A trifoliolate leaf of N. humboldtiana subsp. humboldtiana B flower of N. humboldtiana subsp. humboldtiana C flower of N. humboldtiana cf. subsp. obliqua from Chimborazo / Ecuador D flower of N. humboldtiana subsp. obliqua from Cajamarca / Peru E inflorescence of N. ramirezii with putative pollinator F flower of N. ramirezii G flower of N. solaria H habit of N. solaria. Photo credits: A-C X. Cornejo D T. Henning E, F: R. Ripley G, H P. Gonzales.