taxonID	type	description	language	source
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	diagnosis	Cosmos harkerae resembles C. longipetiolatus and C. sherffii, but differs from them by its fusiform to subglobose tuberous roots 0.5 – 2.3 × 2 – 4.2 cm, petioles 0.6 – 5 cm long, opposite or alternate lateral pinnae segments of the leaves with the basal lobes often reclinate and pointing backward and resembling stipels, disk florets protected by the first paleae series and showing overall a tubular appearance, and light brown to reddish brown cypsela.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	materials_examined	Type: — MEXICO. Guerrero: Olinalá, Xixila, km 19.5 de la carretera Papalutla-Xixila, cuenca del río Atoyac-Alto Balsas, 1640 m, 17.955740 ºN, - 98.849043 ºW, 31 August 2017 (fl, fr), A. Castro-Castro, S. C. Saucedo-Heredia & J. Esteban 4305 (holotype CIIDIR!; isotypes, FCME!, HUMO!, IBUG!, IEB!, MEXU!, OAX!, QMEX!, TEX!, UAGC!, XAL!).	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	description	Perennial herbs, 50 – 112 cm, from a rhizome and tuberous roots, the roots 0.5 – 2.3 × 2 – 4.2 cm, fusiform to subglobose. Stems erect, simple, 19 – 53 cm, terete, sulcate, tomentose, sometimes glabrate on upper parts or old stems, trichomes, simple, multicellular. Leaves 4 – 8 pairs per stem, opposite, petiolate, membranaceous, lanceolate to deltate, rarely ovate in outline, 1.5 – 18 × 1 – 19 cm, 1 – 2 pinnatifid, 3 – 5 (– 7) - pinnate, tapering, acute to rounded, acuminate in the apex, margin antrorse spinulose-ciliate, somewhat thickened, lamina glabrous or appressed-hispid especially beneath and along the mid vein; petiole 0.6 – 5 cm, narrowly winged, channelled; central pinna 1 – 13 - lobed, lanceolate or ovate even elliptic in outline, sometimes linear, the lobes entire or with one short secondary lobe, acuminate, 1.3 – 13 × 0.2 – 10 cm; lateral pinnae 1 – 9 - lobed, lanceolate to elliptic, rarely linear in outline, the lobes entire or with one short secondary lobe, acuminate, opposite or alternate, 1 – 9.7 × 0.2 – 6.3 cm, the basal lobes often reclinate and pointing backward, resembling stipels. Capitulescence terminal or axillary, of 1 – 2 - capitula, peduncles 17 – 45 cm, slender, glabrous. Capitula radiate, heterogamous, subhemispheric, 4 – 8 cm wide across the extended rays. Involucre 1.1 – 2.2 cm wide, 0.5 – 1.2 cm high, cup-shaped. Phyllaries biseriate; outer series 7 – 8, green, 4.3 – 10 × 0.8 – 2.8 mm, ensiform to oblong, ascending to inclined, glabrous, shiny, with 3 – 5 resiniferous ducts on the abaxial face, apices acute; inner series 6 – 8, translucent, pale yellow to light green, glabrous, conspicuously striped, 5.4 – 11 × 1.2 – 3 mm, ensiform to oblong, apex acute. Receptacle convex, paleaceous, 1.4 – 3 mm high, 4 – 6.8 mm wide. Paleae translucent yellow, 9.8 – 14.8 × 0.9 – 2.5 mm, persistent and resembling the inner phyllaries. Ray florets 8, uniseriate, sterile, limb obovate to elliptic, pale lilac, apex obtuse, entire to irregularly toothed, 1.9 – 3.9 × 0.5 – 1.6 cm, 3 ribbed outside, glabrous. Disk florets 34 – 46, hermaphrodite, 6.9 – 8.1 mm, 1.3 – 2 mm diameter of extended lobes, yellow, protected by the first paleae series, showing a tubular appearance; tube 1.5 – 3 × 0.6 – 0.7 mm, glabrous; throat 5.4 – 5.5 × 0.7 – 1.1 mm, glabrous; lobes 5, 0.8 – 1 mm long, erect to slightly involute, triangular, acute, margins ciliate, slightly revolute. Anthers 5, 1.8 – 2.3 mm long, apical appendages ovate, cylinder brown; pollen grain yellow; filaments 1.5 – 2 mm long, pubescent throughout. Style 5 – 5.8 mm long; stigma 0.9 – 1.3 mm long, lobes yellow, apices acute, penicillate, papillate beneath and along margins. Cypsela 6.9 – 19.1 × 0.8 – 2 mm, light brown to reddish brown, fusiform, tetrangular, with deep furrows between angles, carpopodium annular; pappus awns 2, 0.8 – 3.5 mm long, each with 6 – 14 retrorse barbs, often loosening.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	distribution	Distribution, habitat and phenology: — Cosmos harkerae has been collected in northwestern Guerrero, at the transition zone between the Balsas Basin and the SMS, biogeographical provinces (Figure 3). It grows on northwestfacing slopes in oak forest, with deep, clayed and reddish soil. It is associated with Bessera elegans Schult. f., Begonia monophylla Pav. ex A. DC., Brongniartia sp., Cosmos purpureus (DC.) Benth. & Hook. f. ex Hemsl., Euphorbia campestris S. Geuns, E. sphaerorhiza Benth., Eysenhardtia polystachya (Ortega) Sarg., Hypenia violacea Mart. Gord. & S. Valencia, Mammillaria albilanata Backeb., Mesosphaerum suaveolens (L.) Kuntze, Mimosa sp., Pinguicula heterophylla Benth., Polianthes geminiflora (Lex.) Rose, Sessilanthera citrina Cruden, Vachellia pennatula (Schltdl. & Cham.) Seigler & Ebinger, Vitex mollis Kunth, and Zornia sp. The plants grow at elevations between 1290 and 1810 m. Cosmos harkerae flowers in August and early September, while fruiting occurs from September to December.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	etymology	Etymology: — This is the second species of Cosmos named after a female botanist. The name C. steenisiae Veldkamp in Veldkamp & Kreffer (1991: 479) was dedicated to Maria Johanna van Steenis-Kruseman. Now, we honor Professor Mollie F. Harker of the Institute of Botany at the Universidad de Guadalajara. Mollie advanced the knowledge of Mexican Asteraceae, and with dedication she trained a new generation of botanists.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	discussion	Taxonomic relationships: — Cosmos harkerae is a geophyte growing from a short rhizome with tuberous roots, and therefore it belongs to C. sect. Discopoda. It is characterized by a combination of characters which include fusiform to subglobose tuberous roots, long petioles 0.6 – 5 cm long, opposite or alternate lateral pinnae segments of the leaves with the basal lobes often reclinate and pointing backward and resembling stipels, disk florets protected by the first paleae series and showing a tubular appearance, and light brown to reddish brown cypselae. Morphologically, C. harkerae shares similarities with C. longipetiolatus and C. sherffii. Table 1 and Figure 4 show a morphological comparison among these species. Furthermore, the key presented in the following lines allows the identification of the taxa within C. sect. Discopoda. Based on the biogeographic regionalization by Morrone et al. (2017), all three species grow in the SMS (Figure 3). Cosmos longipetiolatus is endemic to the western end of the mountain range in the state of Jalisco, in a transition zone between the pine and oak forest and the cloud forest. Cosmos sherffii inhabits the Pinus - Quercus - Juniperus forest at the eastern portion of the SMS, in the state of Oaxaca. In contrast, C. harkerae is found in the central region of the SMS, on the slopes facing the Balsas Basin in the state of Guerrero. Here, a tropical Quercus forest develops (Figure 3). The TMVB and the SMS limit the Balsas Basin. Temperate Pinus and Quercus forest dominate the first two provinces, above the elevation of 1000 m. In contrast, the tropical dry forest covers the Balsas Basin. Morrone (2017) suggested a relationship among the SMS, the TMVB and the Balsas Basin along the contact zone.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	conservation	Conservation assessment: — Cosmos harkerae has been collected in five locations close to each other and probably all form just one population with a broader geographic range (Figure 3). In all the sites explored, we found numerous plants. Based on the criteria of the IUCN (2024), it is proposed to include this species in the Critically Endangered category (CR / B 1 a), taking into consideration the values calculated for the EOO (10.716 km 2) and Endangered (EN / B 2 a) considering the value of the AOO (20 km 2), both based on 2 × 2 km cells. Most likely, Cosmos harkerae has a wider geographical range. A morphologically similar plant was identified on the citizen science platform iNaturalistMx. The observation was made in the municipality of Madero, Michoacán, almost 280 km west in a straight line from the type locality. The area falls in the transition zone to the Balsas Basin but now with the TMVB (Figure 3). It was not possible to visit the site, and we did not find herbarium specimens in the consulted herbaria.	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
D14E87C9FF857F5EFF676A26FAA00BA1.taxon	materials_examined	Additional material examined (paratypes): — MEXICO. Guerrero: Olinalá, Papalutla, 14 km al SE de Papalutla, crucero Olinalá-Xixila-Papalutla, 1290 m, 17.995115 ºN, - 98.847852 ºW, 7 September 1993 (fl), M. Luna-Flores 692 (FCME); 6.6 km al SE de Papalutla, 1550 m, 18.017040 ºN, - 98.884366 ºW, 1 December 2006 (fr), O. Hinojosa-Espinosa 251 (FCME); Xixila, crucero Xixila-Papalutla-Olinalá, 1400 m, 17.953444 ºN, - 98.853165 ºW, 17 August 2007 (fl), O. Hinojosa-Espinosa 137 (FCME); crucero Olinalá-Xixila-Papalutla, 1400 m, 17.953444 ºN, - 98.853165 ºW, 21 August 1992 (fl), J. Calónico S. 232 (FCME); km 21 de la carretera Papalutla-Xixila, laderas cercanas a la comunidad de Xixila, 1810 m, 17.949980 ºN, - 98.850276 ºW, 31 August 2017 (fl, fr), A. Castro-Castro, S. C. Saucedo-Heredia & J. Esteban 4311 (CIIDIR). Observation in iNaturalistMx: — MEXICO. Michoacán: Madero, southeast Las Mesas, 1965 m, 19.374373 ºN, - 101.020338 ºW, 8 September 2016 (fl), Acatecatl (https: // mexico. inaturalist. org / observations / 5038567).	en	Castro-Castro, Arturo, Rodríguez, Aarón, Neri-Mondragón, Alberto Yahir, Siordia-González, Nadia Elizabeth (2025): A new species of Cosmos section Discopoda (Coreopsideae, Asteraceae) from Guerrero, Mexico. Phytotaxa 725 (1): 91-100, DOI: 10.11646/phytotaxa.725.1.8, URL: https://doi.org/10.11646/phytotaxa.725.1.8
