Heteropsis Kunth

Soares, M. Lourdes, Mayo, Simon J. & Gribel, Rogério, 2013, A Preliminary Taxonomic Revision of Heteropsis (Araceae), Systematic Botany (Basel, Switzerland) 38 (4), pp. 925-974 : 939-940

Heteropsis Kunth , Enum. Pl. 3: 59. (1841).

— TYPE species: H. salicifolia Kunth (1841) .

Secondary hemi-epiphytes, stem quadrangular to cylindric, usually longitudinally striate, axillary buds introrse to extrorse with an acute, rounded or truncate apex; roots dimorphic (anchor roots and feeder roots). Leaves distichous, numerous, petiole usually short, free, canaliculate and geniculate apex, sheath usually congenitally fused to the subtending internode, rarely with a fully developed free-sheathed petiole ( H. melinonii , H. steyermarkii ); leaf blade linear, obovate, elliptic, oblong to oblanceolate, coriaceous to subcoriaceous, apex acute, acuminate to attenuate, base attenuate, cuneate to rounded, green to yellowish-green, rarely glaucous abaxially ( H. melinonii , H. steyermarkii ), midrib insculpted to sulcate, primary lateral and interprimary veins parallel-pinnate, forming an infra-marginal collective vein near the margin, with 1(–2) marginal veins often present externally, finer venation reticulate. Inflorescence solitary, terminal and axillary, flowering shoot stem slender to thick, usually bearing several cataphylls which are caducous after anthesis, peduncle short to short, cylindric; spathe ovate to elliptic to ovate or oblong, convolute to semi-convolute, white to yellow, apex acuminate to cuspidate, opening at anthesis and deciduous afterwards; spadix erect, free, cylindric to ellipsoid, shorter than spathe, white to yellow, exceptionally rose to vinaceous ( H. steyermarkii ), usually stipitate, stipe usually short, rarely absent. Flowers hermaphrodite, perigone absent. Stamens 4 per flower or less by abortion, free, filament flattened, connective slender, anthers ovate to ellipsoid, dehiscing by apical slits, inserted at the apex of the connective. Gynoecium obpyramidal to prismatic, with four to six sides, usually truncate apically; ovary incompletely 2-locular, locules usually filled with a translucid mucilage; ovules anatropous, collateral; placentation basal to sub-basal, exceptionally axile, stylar region dense, broader than the ovary; stigma discoid to sub-discoid, elliptic to oblong. Fruit a berry, obovoid to obpyramidal to somewhat prismatic, 1–4-seeded, yellow to orange or red, stylar region broad with a stigmatic scar. Seed ovoid to obovoid or ellipsoid, usually surrounded by a sweet mucilaginous, transparent, yellowish to orange pulp, testa smooth to rugose or foveolate, embryo large, endosperm absent.

KEY TO THE SPECIES Of HETEROPSIS

1. Petiole 4 – 9 cm long including sheath............................................................................... 16. H. steyermarkii

1. Petiole equal to or less than 3.0 cm long, lacking sheath.............................................................................. 2

2. Leaf blade equal to or greater than 30.0 cm long................................................................................. 3

3. Leaf blade equal to or less than 3.0 cm wide....................................................................... 6. H. linearis

3. Leaf blade equal to or greater than 4.0 cm wide.............................................................................. 4

4. Leaf blade linear to oblong, leaf 5–9 cm wide, collective vein 0.25– 0.5 mm distant from leaf margin................ 8. H. macrophylla

4. Leaf blade elliptic, leaf width 9–24 cm, collective vein 0.95 –2.05 mm distant from leaf margin.................................. 5

5. Leaf blade less than or equal to 32.0 cm long............................................................. 11. H. reticulata

5. Leaf blade greater than or equal to 35.0 cm long........................................................... 18. H. vasquezii

2. Leaf blade less than 30.0 cm long.............................................................................................. 6

6. Infra-marginal vein distance from margin equal to or greater than 1.3 mm ...................................................... 7

7. Plant occurring in Atlantic Forest of Eastern and Northeastern Brazil........................................................ 8

8. Flowering spadix 3.5 cm long or more, 1.0 – 1.4 cm diam, petiole margin smooth, no sinuations.................... 5. H. flexuosa

8. Flowering spadix up to 3.5 cm long, up to 0.8 cm diam, petiole margin sinuate at least towards apex......................... 9

9. Leaf blade 3.5–7 cm wide, oblong, oblong-ovate to oblong-obovate...................................... 9. H. oblongifolia

9. Leaf blade 1.8–4.0 cm wide, lanceolate to oblanceolate................................................. 14. H. salicifolia

7. Plant occurring elsewhere........................................................................................... 10

10. Axillary buds acute at apex, internodes subquadrangular to quadrangular in section, leaf shortly attentuate to obtuse at base......................................................................... 11

11. Infra-marginal vein up to 1.6 mm distant from margin, internodes of flowering shoot 0.18 cm or more diam, peduncle 0.5–0.6 cm long, spathe 3.49–3.51 cm long.................................................. 2. H. croatii

11. Infra-marginal vein 2.0 mm or more distant from margin, internodes of flowering shoot up to 0.17 cm diam, peduncle 0.09–0.1 long, spathe 2–2.5 cm long....................................................... 13. H. robusta

10. Axillary buds rounded at apex, internodes subcylindric to cylindric in section, leaf cuneate at base........................ 12

12. Spathe 2.5 – 5.0 cm long, petiole 0.5 –0.8 cm long, leaf blade 0.22–0.28 mm thick, internodes of flowering shoot 0.3 cm diam, peduncle 1.0 – 1.5 cm long, spadix 1.0– 1.5 cm diam, spadix stipe 0.15–0.2 cm long........... 3. H. duckeana

12. Spathe 7.0 – 8.0 cm long, petiole 0.2 –0.4 cm long, leaf blade 0.12–0.16 mm thick, internodes of flowering shoot 0.18 cm diam, peduncle 0.3 – 0.7 cm long, spadix 0.7 cm diam, spadix stipe 0.03 –0.06 cm long......... 7. H. longispathacea

6. Infra-marginal vein less than 1.3 mm distant from margin................................................................... 13

13. Leaf 9 cm wide or more............................................................................................. 14

14. Leaf blade linear to oblong, infra-marginal vein 0.25 – 0.5 mm from margin................................ 8. H. macrophylla

14. Leaf blade elliptic or ovate, infra-marginal vein 0.95 –1.25 mm from margin........................................... 15

15. Leaf blade 22.5 cm long or more, 9.0 cm wide or more, petiole margin smooth, no sinuations............. 11. H. reticulata

15. Leaf blade up to 21.0 cm long, up to 9.0 cm wide, petiole margin sinuate at least towards apex........... 17. H. tenuispadix

13. Leaf less than 9 cm wide............................................................................................ 16

16. Plant from Atlantic forest of Eastern and Northeastern Brazil............................................. 12. H. rigidifolia

16. Plant from elsewhere, not Atlantic forest of Brazil................................................................. 17

17. Spadix 0.8–1.0 cm diam................................................................................... 18

18. Leaf blade linear, axillary buds rounded to truncate at apex................................................ 19

19. Leaf blade 1.5 – 3.0 cm wide, axillary buds 2.0–3.0 mm long, petiole 0.3–1.0 cm long, infra-marginal vein 0.7– 0.8 mm from margin.............................................. 6. H. linearis

19. Leaf blade 5.0 – 9.0 cm wide, axillary buds 5.0–8.0 mm long, petiole 1.0–3.0 cm long, infra-marginal vein 0.25–0.5 mm from margin......................................... 8. H. macrophylla

18. Leaf blade lanceolate, ovate, elliptic, oblong or oblanceolate, axillary buds acute at apex........................ 20

20. Leaf blade oblong to oblanceolate, internodes cylindric to subcylindric in section, petiole 0.4– 0.6 cm long, peduncle 0.6 – 1.0 cm long, spathe white-cream, 4.0– 4.5 cm long................................................................... 4. H. ecuadorensis

20. Leaf blade lanceolate, ovate or elliptic, internodes quadrangular to subquadrangular in section, petiole 0.1–0.3 cm long, peduncle 0.2 –0.5 cm long, spathe yellow, 1.5 –2.8 cm long.................................................................... 15. H. spruceana

17. Spadix 0.3 –0.7 cm diam................................................................................... 21

21. Internodes quadrangular to subquadrangular, petiole 0.1– 0.3 cm long, spathe 1.5– 2.8 cm long....... 15. H. spruceana

21. Internodes cylindric to subcylindric, petiole 0.3–1.0 cm long, spathe 2.0– 4.5 cm long (unknown in H. reticulata .).......................................................................... 22

22. Leaf blade oblong to oblanceolate, petiole 0.30– 0.31 cm long.................................. 1. H. boliviana

22. Leaf blade lanceolate, ovate or elliptic, petiole 0.3–1.0 cm long......................................... 23

23. Peduncle 0.3 – 0.5 cm long, leaf blade 4.0–9.0 cm wide, petiole 0.6 – 1.0 cm long, infra-marginal vein 1.0– 1.25 mm distant from margin, spadix ellipsoid, spadix stipe 0.4– 0.7 cm long.................................................... 17. H. tenuispadix

23. Peduncle 0.07 – 0.21 cm long, leaf blade 2.5– 4.5 cm wide, petiole 0.3–0.7 cm long, infra-marginal vein 0.5– 1.0 mm distant from margin, spadix cylindric, spadix stipe 0.2– 0.25 cm long............................................................... 24

24. Axillary buds acute at apex, leaf blade lanceolate, 0.13– 0.21 mm thick, visible external marginal vein 1, peduncle 0.07–0.12 cm long, spadix 2– 2.5 cm long....................................................... 10. H. peruviana

24. Axillary buds rounded at apex, leaf blade ovate to elliptic, 0.24–0.62 mm thick, visible external marginal vein absent, peduncle 0.2 cm long, spadix 1.8 cm long......................................................... 11. H. reticulata