Icacinaceae Miers

Rio, Cédric Del, Stull, Gregory W. & Franceschi, Dario De, 2020, Survey of the fruits and endocarps of Icacinaceae (Lamiids, Icacinales), European Journal of Taxonomy 645, pp. 1-130 : 9-10

Family Icacinaceae Miers

Figs 6–34

Description

FRUIT. Drupaceous, elliptical to globose, asymmetrical at the apex, occasionally including an accrescent perianth; laterally compressed, mainly red-black when mature; glabrous or pubescent with a wide diversity of hair shapes. Calyx usually persistent, occasionally separated from the fruit by a gynophore.

ENDOCARP. Cream to brown, bilaterally symmetrical, unilocular, single-seeded, elliptical to globose in lateral view, lenticular to globose in transverse section. Keel often surrounding the endocarp in the plane of symmetry, occasionally faintly apparent or with a channel. Apex acute to flattened, asymmetrical or slightly asymmetrical; base symmetrical or cleft on one side, rounded to acute. Outer surface of the endocarp smooth, rugose, ridged, or pitted (or often ridged and pitted). Endocarp primary vascular bundle positioned outside the endocarp wall (in the mesocarp), often in a channel on the keel, or embedded within the endocarp wall. Endocarp wall composed of interlocking digitate and sclerotic cells with different orientations, rarely homogeneous. Locule surface (= inner endocarp surface) macromorphology smooth, lacunate or with tubercles protruding into the locule. Locule surface micromorphology smooth, papillate or with inflated cells, occasionally hairy.

Key to genera of Icacinaceae s.str.

1. Endocarp wall homogeneous comprised of isodiametric cells .............................. Cassinopsis Sond. – Endocarp wall not homogeneous or cells not exclusively isodiametric ........................................... 2

2. Hairs present on the locule surface ................................................................................................... 3 – Hairs absent from the locule surface ................................................................................................ 4

3. Endocarp width ca 40 mm, endocarp wall more than 700 µm thick ........................ Lavigeria Pierre – Endocarp width ca 13 mm, endocarp wall less than 400 µm thick ................................ Leretia Vell.

4. Locule surface papillate .................................................................................................................... 5 – Locule surface not papillate .............................................................................................................. 6

5. Outer endocarp surface pitted ........................................................................................................... 7 – Outer endocarp surface not pitted ..................................................................................................... 8

6. Hairs-like unit present on the endocarp surface ................................................. Pleurisanthes Baill. – Hairs-like unit absent from the endocarp surface ............................................................................. 9

7. Tubercles bullate ....................................................................................................... Miquelia Meisn. – Tubercles spiny, cylindrical, peg-shaped or elongate-flattened ........................ Pyrenacantha Hook.

8. Endocarp primary vascular bundle embedded within endocarp wall ............................. Iodes Blume – Endocarp primary vascular bundle outside endocarp wall or in a channel .................................... 10

9. Outer endocarp surface pitted ..........................................................................................................11 – Outer endocarp surface not pitted ................................................................................................... 12 10. Outer endocarp surface completely smooth ................................................................... Iodes Blume – Outer endocarp surface ridged or rugose, irregular ........................................................................ 13

11. Pits within shallow mounds slightly protruding inside the locule .......................... Phytocrene Wall. – Pits within tubercles protruding inside the locule ........................................................................... 14

12. Endocarp thickness> 12 mm ..................................................................................... Icacina A.Juss. – Endocarp thickness <10 mm .......................................................................................................... 15

13. Endocarp length ca 12 mm .................................................................. Hosiea Hemsl. & E.H.Wilson – Endocarp length> 15 mm ............................................................................................................... 16

14. Tubercles bullate ................................................................................................. Stachyanthus Engl. – Tubercles spiny, cylindrical, peg-shaped or elongate-flattened ........................ Pyrenacantha Hook.

15. Endocarp ridged and reticulate ....................................................................................................... 17 – Endocarp rugose, irregular .............................................................................................................. 18

16. Endocarp almost smooth, irregularly rugose but without clear protuberant structures ...................... .................................................................................................................. Sarcostigma Wight & Arn. – Endocarp rugose with clear protuberant structures or ridged ......................................................... 19

17. Endocarp oblong .................................................................................... Alsodeiopsis Oliv. in Benth. – Endocarp elliptical .......................................................................................................................... 20

18. Endocarp apex with prominent bulge or pores ............................................................................... 21 – Endocarp apex without ornamentation .......................................................................... Mappia Jacq.

19. Endocarp rugose, irregular ....................................................................... Mappianthus Hand. -Mazz. – Endocarp ridged with a reticulate or diffuse ornamentation ................................ Rhyticaryum Becc.

20. Endocarp length ca 9 mm, 4–5 areoles formed by ridges on each face .............................................. ........................................................................................................... Natsiatum Buch. -Ham. ex Arn.

– Endocarp length> 11 mm, 20–30 areoles formed by ridges on each face .......................................... .................................................................................................... Vadensea Jongkind & O.Lachenaud

21. Endocarp with subapical pores .................................................. Vadensea Jongkind & O.Lachenaud – Endocarp with apical bulge ............................................................................................................ 22

22. Ornamentation bullate, occuring in Madagascar............................. Desmostachys Planch. ex Miers – Ornamentation more granular, occuring in Asia ............................................... Nothapodytes Blume

Figures

Fig. 6. Fruits of Icacinaceae Miers. 1–9. Alsodeiopsis mannii Oliv. (N. Hallé & J.F. Villiers 4579). 1. Dried fruit, lateral view. 2–6. Endocarp. 2. Lateral view showing a reticulate pattern of ridges. 3. Dorsal view showing a keel surrounding the endocarp. 4. Opposite lateral view. 5. Apical view. 6. Basal view. 7. SEM image of seed and pericarp in transverse section. 8. Detail of the same section showing the mesocarp on the top and the endocarp wall at the bottom. 9. SEM image of the vascular bundle in a channel (arrow). – 10–18. Alsodeiopsis poggei Engl. (P. Sita 1872). 10. Dried fruit, lateral view. 11–15. Endocarp. 11. Lateral view showing a reticulate pattern of ridges. 12. Dorsal view showing a keel surrounding the endocarp. 13. Opposite lateral view. 14. Apical view. 15. Basal view. 16. SEM image of simple the hairs on the epicarp surface. 17. SEM image of the endocarp wall in transverse section. 18. SEM image of the vascular bundle in a channel (arrow). – 19–27. Alsodeiopsis staudtii Engl. (J.J.F.E. de Wilde 8304). 19. Dried fruit, lateral view. 20–25. Endocarp. 20. Lateral view showing a reticulate pattern of ridges. 21. Dorsal view showing a keel surrounding the endocarp. 22. Opposite lateral view. 23. Apical view. 24. Basal view. 25. Lateral view showing the vascularisation on the ridges. 26. SEM image of the pericarp in transverse section with a vascular bundle (arrow). 27. SEM image of the simple hairs on the epicarp surface. Images taken from Del Rio (2018). Scale bars: 1–6, 10–15, 19–24 = 10 mm; 7, 25 = 1 mm; 9, 18, 26 = 500 μm; 8, 16–17, 27 = 200 μm.