Key to the native species of Magnolia in Guatemala

1 Petioles with conspicuous stipular scar, polyfollicles with circumscissile dehiscence ( Magnolia sect. Talauma)............................2

- Petioles without stipular scar, polyfollicles with dorsal dehiscence ( Magnolia sect. Magnolia).......................................................6

2 Carpels 7–12, stamens 40–44.............................................................................................................................................. M. quetzal

- Carpels 22–70, stamens 75–248 .........................................................................................................................................................3

3 Stamens 198–248, carpels 61–70, specie known from tropical rainforest at elevation <1200 m a.s.l. in Chiapas state of Mexico and Guatemala .................................................................................................................................................................... M. lacandonica

- Stamens 75–108, carpels 22–42, species from cloud forest at elevation ≥ 1200 m in northern Guatemala ......................................4

4 Flowers 20.2–22.2 cm in diameter, leaves 40.0–42.0 × 18.9–23.0 cm, carpels 38–42, floral bracts 2................................... M. ottoi

- Flowers 12.5–16.0 cm in diameter, leaves 19–34.5 × 8.8–15 cm, carpels 22–32, floral bracts 1......................................................5

5 Stamens 75–76, carpels 30–32, styles readily deciduous, spathaceous bract length 3.9 cm, leaves 22.5 × 12.5 cm, leaf apex obtuse.......................................................................................................................................................................... M. steyermarkii

- Stamens 92–103, carpels 22–28, styles persistent, spathaceous bract length 4.8–6.3 cm, leaves 19–29.3 (–34.5) × 8.8–12.9 (–15) cm, leaf apex retuse ....................................................................................................................................................... M. quichensis

6 Mature fruit densely pubescent ..........................................................................................................................................................7

- Mature fruits glabrous to glabrescent .................................................................................................................................................9

7 Mature leaves 30.0–43.0 cm long ........................................................................................................................................ M. mayae

- Mature leaves 7.5–23.0 cm long.........................................................................................................................................................8

8 Fruits 6.8–8.8 cm long, stamens 103–111, carpels 47–55 (–58) ...................................................................................... M. veliziana

- Fruits 3.0– 5.7 cm long, stamens 61–93, carpels 23–28............................................................................................... M. hondurensis

9 Leaves broadly obovate, elliptical and ovate, leaf margin revolute .................................................................................................10

- Leaves oblong, lanceolate, elliptical to narrowly obovate, leaf margin not revolute.......................................................................12

10 Flowers 9–10 cm in diameter, leaves glabrous on both surfaces, apex emarginate, fruits 4.4 cm long............................... M. javieri

- Flowers 12.0–15.0 cm in diameter, ferruginous leaves on the underside (at least the veins), apex acute, round to apiculate, fruits 4.8–7.5 cm long ................................................................................................................................................................................11

11 Petals 8.3–8.5 cm long, stamens 73–76, carpels 34–39, fruits 7.0– 7.5 cm long............................................................. M. archilana

- Petals 6.5–7.0 cm long, stamens 92–98, carpels 22–25, fruits 4.8–5.2 cm long..................................................... M. guatemalensis

12 Stamens 53–94..................................................................................................................................................................................13

- Stamens (97–)100–120.....................................................................................................................................................................17

13 Fruit follicles 40–50 ........................................................................................................................................................................14

- Fruit follicles 22–35 .........................................................................................................................................................................16

14 Leaves ≤ 10 cm long................................................................................................................................................. M. tribouillierana

- Leaves 10–24 cm long......................................................................................................................................................................15

15 Petals 8–10, flowers 15.0–17.0 cm in diameter, fruits 6.0–8.0 × 2.9–3.1 cm ........................................................... M. weerakitiana

- Petals 6, flowers 6–10 cm in diameter, fruits 4–6 × 2–4 cm .......................................................................................... M. yoroconte

16 Spathaceous bracts 3, leaf tip acute to obtuse, lateral veins 11–12, pubescent to glabrescent carpels, reddish floral staminophore .. ............................................................................................................................................................................... M. montebelloensis

- Spathaceous bracts 2, abruptly acuminate leaf apex, 13–17 lateral veins, glabrous carpels, purple floral staminophore................... ......................................................................................................................................................................................... M. poqomchi

17 Spathaceous bracts 1, globose fruits, relation of length to width 1.66:1, glabrous, 5.3–5.4 cm long, lateral leaf veins 15–17........... .................................................................................................................................................................................. M. oscarrodrigoi

- Spathaceous bracts 2, oblongoid fruits, relation of length to width 2.16:1, glabrescent, 5.5–6.5 cm long, lateral leaf veins 10–14 .. ............................................................................................................................................................................ M. faustinomirandae