Pyrenacantha Hook.
Creators: name: Rio, Cédric Del
name: Stull, Gregory W.
name: Franceschi, Dario De
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Icacinales
Icacinaceae
Pyrenacantha

description: Genus Pyrenacantha Hook.
Figs 23.10–23.27, 24–30, 31.1–31.9
Description
FRUIT. Elliptical to globose, apex accrescent elongate, sometimes widely inflated, laterally compressed or not, yellow to black when mature. Epicarp puberulent to pilose, with simple hairs, small ovoid hairs with an acuminate apex, long and thin hairs, or uncinate hairs, yellow, occasionally red or white; occasionally shriveled when dry, revealing the underlying reticulum of endocarp ridges. Calyx absent or persistent, often separated from the fruit by more or less extended gynophore.
ENDOCARP.Brown to cream, elliptical-ovoid to globose, rarely deltoid in lateral view, lenticular to globose in transverse section. Keel, more or less visible, surrounding the endocarp in the plane of symmetry. Apex asymmetrical in lateral view; base symmetrical. Outer surface of the endocarp pitted and ridged, with the ridges delimiting a reticulate pattern, which in general surrounds the pits. Sometimes the ridges are not visible except at the apex. Pits more or less circular, in longitudinal lines or randomly distributed, each pit associated with a tubercle protruding into the locule; tubercles spiny, peg-shaped, cylindrical, or elongate-flattened. Vasculature of the endocarp free; primary vascular bundle positioned outside the endocarp wall. Endocarp wall mainly with three stratified cell layers. Locule surface often with regularly spaced and rounded to large papillae, occasionally only present at the apex of the tubercles, smooth in some cases, not clearly lacunate.
Key to the genus Pyrenacantha
1. Endocarp elliptical-ovoid, obovoid or globose in lateral view ......................................................... 2
– Endocarp deltoid in lateral view ......................................................................................................... ...................................................... P. macrocarpa (A.Chev. ex Hutch. & Dalziel) Byng & Utteridge
2. Tubercles ± 1 mm long, elongate-flattened or peg-shaped ............................................................... 3
– Tubercles> 1 mm long, spiny or cylindrical ..................................................................................... 4
3. Tubercles peg-shaped ........................................................................................................................ 5
– Tubercles elongate-flattened ............................................................................................................. 6
4. Tubercles spiny ................................................................................................................................. 7
– Tubercles cylindrical ......................................................................................................................... 8
5. Locule surface smooth, tubercles capitate at the apex, often bifid ..................................................... .......................................................................................... P. klaineana Pierre ex Exell & Mendonça
– Locule surface with papillae, tubercles not capitate or bifid at the apex .......................................... 9
6. Endocarp ovoid to globose in lateral view, fewer than 50 pits per face ......................................... 10
– Endocarp elliptical to obovoid, more than 50 pits per face .............................................................11
7. Pits small, up to 400 µm in diameter .............................................................................................. 12
– Pits wider, up to 1450 µm in diameter ............................................................................................ 13 8. Endocarp ca 9 mm in length, with no reticulation ............................................. P. sylvestris S.Moore
– Endocarp more than 10 mm in length, with reticulation ................................................................ 14
9. Endocarp with more than 200 pits per face ........................................................... P. vogeliana Baill.
– Endocarp with fewer than 190 pits per face ................................................................................... 15
10. Endocarp wall 275–325 µm thick, at least 40 pits per face ................................................................ ....................................................................................... P. anhydathoda (Villiers) Byng & Utteridge
– Endocarp wall 420–500 µm thick, up to 36 pits per face ................................................................... ............................................................................................. P. gossweileri (Exell) Byng & Utteridge
11. Endocarp obovoid, ca 18.5 mm in length, with a reticulum of ridges enclosing 37–55 areoles ........ .................................................................................................. P. soyauxii (Engl.) Byng & Utteridge
– Endocarp elliptical, ca 14.8 mm in length, with a reticulum of ridges enclosing 5–7 areoles ........... ........................................................................................... P. thomsoniana (Bail.) Byng & Utteridge
12. Endocarp width ca 15 mm ............................................................................ P. longirostrata Villiers
– Endocarp width ca 7.2 mm ............................................................................................................. 16
13. Endocarp wall less than 400 µm thick ............................................................................................ 17
– Endocarp wall more than 400 µm thick .......................................................................................... 18
14. Endocarp length ca 19 mm, more than 100 pits per face ................................ P. laetevirens Sleumer
– Endocarp length less than ca 12 mm, fewer than 45 pits per face .................................................. 19
15. Endocarp length ca 15.4 mm, endocarp wall 290–300 µm thick, ca 100 pits per face ...................... ....................................................................................... P. rakotozafyi Labat, El-Achkar & R.Rabev.
– Endocarp length less than ca 14.4 mm, endocarp wall more than 400 µm thick, more than 120 pits per face ............................................................................................................................................ 20
16. Endocarp ca 11 mm long ................................................................................................................ 21
– Endocarp ca 14 mm long .................................................................................... P. lebrunii Boutique
17. Ca 80–93 pits per face ................................................... P. tropophila Labat, El-Achkar & R.Rabev.
– Ca 107–114 pits per face ..................................................................................... P. capitata H.Perrier
18. Endocarp lenticular in transverse section, surface ridged and pitted or only pitted ....................... 22
– Endocarp globose in transverse section, surface only pitted .......................................................... 23
19. Tubercle length more than 2 mm, endocarp length ca 12 mm, endocarp wall more than 300 µm thick .................................................................................................................... P. cordicula Villiers
– Tubercle length less than 2 mm, endocarp length ca 10.8 mm, endocarp wall less than 300 µm thick ............................................................................................................... P. staudtii (Engl.) Engl.
20. Ridges sharp, pits less than 300 µm in diameter, 170–184 pits on each face ..................................... ......................................................................................................................... P. kaurabassana Baill.
– Ridges rounded, pits more than 300 µm in diameter, 120–140 pits on each face .............................. ............................................................................................................................... P. malvifolia Engl.
21. Endocarp with a prominent median ridge that crosses the endocarp in length ................................... .............................................................................................................................. P. acuminata Engl.
– Endocarp without a prominent median ridge .................................................... P. puberula Boutique
22. Endocarp pitted and ridged, pits elongate ......................... P. humblotii (Baill. ex Grandid.) Sleumer
– Endocarp pitted only, with circular pits ................................................. P. glabrescens (Engl.) Engl.
23. Endocarp with 145–150 pits on each face ..................... P. ambrensis Labat, El-Achkar & R.Rabev.
– Endocarp with 159–173 pits on each face .................... P. andapensis Labat, El-Achkar & R.Rabev.
description: Published as part of Rio, Cédric Del, Stull, Gregory W. & Franceschi, Dario De, 2020, Survey of the fruits and endocarps of Icacinaceae (Lamiids, Icacinales), pp. 1-130 in European Journal of Taxonomy 645 on pages 69-71, DOI: 10.5852/ejt.2020.645, http://zenodo.org/record/3829651