Thurniaceae

Taxonomy

Family name: Thurniaceae A. Engler

Synonym(s): Prioniaceae S. L. Munro & H. P. Linder

Common name(s): thurnia family

*Number of genera/species: 2/4

List of genera records in GRIN-Global

Disseminule

seed

Description

Fruit a loculicidalloculicidal:
type of capsular dehiscence, opening longitudinally through the locules (compare septicidal)
capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
, 1–15 mm long, triangulartriangular:
2D shape—three relatively straight sides with distinct corners; more angular than teardrop-shaped
, angledangular:
2D shape—having sides that meet at acute or obtuse angles  
in transection, usually 3 seeded, sometimes hypanthium present. Pericarppericarp:
fruit wall or fruit coat
smooth.

Seeds fusiformfusiform:
spindle-shaped; broadest at the middle and tapering at both ends
(ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
to broadly ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
in Prionium), tereteterete:
approximately circular in cross section; width and thickness approximately equal
(triagonal in Prionium) in transection, 5–8 mm long, hairlike appendages present at both ends (not appendiculate in Prionium). Seed coat with short, straight hairs (glabrousglabrous:
without hairs
in Prionium).  

Embryo well developed, linearlinear:
(shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide
to broad, straight, 0.3 times the length of the endosperm (or nearly as long in Prionium).

Endosperm copious, mealymealy:
loose, dry, and disintegrating in finely granular pieces like meal or flour
.

Identification features

Fruit
Type capsulecapsule:
a dry, dehiscent fruit derived from a compound ovary
Size range 10–15 mm long
Shape(s) tri angularangular:
2D shape—having sides that meet at acute or obtuse angles  
Surface relief smooth
Seed
Size range 5–8 mm long
Shape(s) fusiformfusiform:
spindle-shaped; broadest at the middle and tapering at both ends
, ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
to broadly ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
Surface relief densely pubescentpubescent:
surface relief—bearing hairs
, glabrousglabrous:
without hairs
Unique features In Thurnia, seeds fusiformfusiform:
spindle-shaped; broadest at the middle and tapering at both ends
and pubescentpubescent:
surface relief—bearing hairs
with hairlike appendages at both ends. In Prionium, seeds ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
to broadly ovateovate:
2D shape—egg-shaped in outline, widest point is towards one end of the organ, the other end tapers gradually, attachment at or near the broad end (compare obovate, ovoid)
and triagonal in transection. 
Other
Embryo well developed, linearlinear:
(shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide
to broad, straight, 0.3 times the length of the endosperm (or nearly as long in Prionium)
Nutritive tissue endosperm copious, mealymealy:
loose, dry, and disintegrating in finely granular pieces like meal or flour

Distribution

Tropical South America.

Distribution map courtesy of Angiosperm Phylogeny Website.

References

Baskin and Baskin 2021Baskin and Baskin 2021:
Baskin C and Baskin J. 2021. Relationship of the lateral embryo (in grasses) to other monocot embryos: A status up-grade. Seed Science Research 31 (3): 199-210. doi:10.1017/S0960258521000209
; Dahlgren et al. 1985Dahlgren et al. 1985:
Dahlgren RMT, Clifford HT, and Yeo PF. 1985. The families of the monocotyledons: structure, evolution, and taxonomy. Springer-Verlag, Berlin. 520 pp.
; Kirkbride et al. 2006Kirkbride et al. 2006:
Kirkbride JH, Jr, Gunn CR, and Dallwitz MJ. 2006. Family guide for fruits and seeds, vers. 1.0. Accessed September 2020-January 2022. URL: https://nt.ars-grin.gov/seedsfruits/keys/frsdfam/index.cfm .
; Kubitzki et al. 1990+Kubitzki et al. 1990+:
Kubitzki K et al., eds. 1990+. The families and genera of vascular plants. 7+ vols. Berlin etc.
; Maas and Maas 2005Maas and Maas 2005:
Maas PJM and Maas H. 2005. Flora Da Reserva Ducke, Amazonas, Brasil: Thurniaceae. Rodrigueacute;sia 56: 207.
; Stevenson and Loconte 1995Stevenson and Loconte 1995:
Stevenson DW and Loconte H. 1995. A cladistic analysis of monocot families. In: Rudall PJ, Cribb PJ, Cutler DF, and Humphries CJ, eds. Monocotyledons: Systematics and Evolution. Royal Botanic Gardens, Kew.

*The number of genera and species is based on Christenhusz and Byng 2016Christenhusz and Byng 2016:
Christenhusz MJM and Byng JW. 2016. The number of known plant species in the world and its annual increase. Phytotaxa 261 (3): 201-217. https://doi.org/10.11646/phytotaxa.261.3.1
, which may differ from the number of genera in GRIN-Global.

  Inflorescence, fruit:   Prionium serratum  (F, mature fruit); Illustration attributed tonbsp;Hooker in Bot. Magaz., Das Pflanzenreich (1906), courtesy ofnbsp;commons.wikimedia.org

Inflorescence, fruit: Prionium serratum (F, mature fruit); Illustration attributed to Hooker in Bot. Magaz., Das Pflanzenreich (1906), courtesy of commons.wikimedia.org

  Embryo:   Thurnia polycephala ; Illustration by K. Parker, Kirkbride et al. (2006)

Embryo: Thurnia polycephala; Illustration by K. Parker, Kirkbride et al. (2006)

  Fruits:   Thurnia sphaerocephala ; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

Fruits: Thurnia sphaerocephala; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

  Seeds:   Thurnia sphaerocephala ; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)

Seeds: Thurnia sphaerocephala; Photo by R. Gibbons, USDA APHIS PPQ, Kirkbride et al. (2006)