Magnolia sect. Macrophylla, Figlar & Noteboom, 2004

Vázquez-García, J. Antonio, Yescas, Reyna Domínguez, Luna-Vega, Isolda, Rodríguez-Ramírez, Ernesto C. & Rodríguez-Pérez, Ciro, 2021, Corncob flower, Magnolia mixteca (M. sect. Macrophylla, Magnoliaceae) a new species endemic to the Alto Balsas Basin (Baja Mixteca), in the Pacific slopes of Oaxaca, Mexico, Phytotaxa 522 (3), pp. 200-210 : 208

Key to species of Magnolia sect. Macrophylla

1. Mature fruit broadly ovoid, broadly ellipsoid to subglobose ............................................................................................................2.

– Mature fruit oblongoid, ovoid or ellipsoid ........................................................................................................................................4.

2. Leaves 50–110 cm long; petals 20 to 23 cm long; gynoecium 4 cm long; stamens (300–)350–580; carpels (44–)50–80; carpel valve margin wide, 0.4–0.5 (–0.7) cm thick; growing at 150–300 m ( US: AL, AR, GA, KY, LA, MS, NC, OH, TN, and VA) .................. .................................................................................................................................................................................... M. macrophylla

– Leaves 25.0–35.0(–40.0) cm long .....................................................................................................................................................3.

3. Petals 10.0–11.0 cm long; carpels 30–40; elev. 1500–1700 m ( Mexico: Nuevo León)......................................... M. nuevoleonensis

– Petals 12–15 cm long, carpels 58–62; elev. 1800– 220 m ( Mexico: Oaxaca).................................................................... M. mixteca

4. Carpels shortly (<0.7 cm) beaked......................................................................................................................................................5.

– Carpels prominently (1.0– 1.5 cm) beaked ........................................................................................................................................6.

5. Multi trunked large shrub, or small leaning trees 8.0–10.0 (–12.0) m; fruit cylindrical to ellipsoid; carpels 20–25(–50), shortly beaked; elevation less than 150 m ( US: Florida).................................................................................................................... M. ashei

– Single upright tall trees 8.0–25.0 m; fruit rhomboid-ovoid; carpels 50–65; elevation 800–1950 m ( Mexico: San Luis Potosí, Querétaro & Hidalgo)............................................................................................................................................... M. rzedowskiana

6. Carpels 42–78....................................................................................................................................................................................7.

– Carpels 80–127..................................................................................................................................................................................8.

7. Stamens 192–216, carpels 42–54 ( Mexico: Tamaulipas).............................................................................................. M. alejandrae

– Stamens 308–352, carpels 60-78 ( Mexico: Veracruz)...................................................................................................... M. vovidesii

8. Fruit dark green to yellow, young fruits glabrescent; stamens 1.3–1.8 cm long; carpels acute to blunt, tip deciduous ( Mexico: Oaxaca)............................................................................................................................................................................. M. dealbata

– Fruit pinkish purplish to dark red, young fruit velvety; stamens 1.9–2.1 cm long; carpels acuminate to caudate, tip sometimes persistent at dehiscence ( Mexico: Hidalgo / Puebla border) ................................................................................................. M. zotictla