Peridiscaceae

Disclaimer

Content is from 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 ., without modification. 
Updates are forthcoming.

Taxonomy

Peridiscaceae J. Kuhlmann

Common name: Peridicus Family.

Number of genera: 2 genera.

Number of species (Mabberley 1997): 2 species (Whittonia guianensis Sandwith & Peridiscus sp.).

Disseminule

Fruit (intact or entire).

Description

Fruits: Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit anthocarpanthocarp:
simple or compound and including some tissue of non-ovarian origin (accessory tissue)
; simple; pseudodrupe (Peridicus, but does Whittonia fruit score here?); without persistent central column; Peridicus within accessory organ(s), or not within accessory organ(s) (Whittonia); within receptacle (disk of Cronquist & Goldberg), or cupule; 1-seeded; 1-seeded; with 3–4-carpellate; with carpels united; with carpels remaining united at maturity; with carpels not radiating at maturity; with carpels remaining connected at stylestyle:
in a flower, the narrow and elongated part of the pistil between the stigma and the ovary; sometimes persisting in fruit
; without sterilesterile:
lacking male and/or female reproductive parts; also, not producing fruit or seed
carpels; not sulcatesulcate:
surface relief—having one or more elongate, relatively narrow and shallow depressions or grooves
; apexapex:
the point farthest from the point of attachment, or the "tip" of an organ
not beaked; indehiscentindehiscent:
not opening on its own, as in a fruit
. Epicarpepicarp:
outer layer of fruit wall or pericarp, if divided into layers; note here used synonymously with exocarp
durable; without armature; without wing(s); without apicalapical:
at or pertaining to the end of the seed or fruit distal from its point of attachment (i.e., base)
respiratory hole. Mesocarpmesocarp:
the middle layer of the pericarp, if divided into layers
present. Endocarpendocarp:
the inner layer of the pericarp, if divided into layers
present; not separating from exocarpexocarp:
outer layer of fruit wall or pericarp, if divided into layers; note here used synonymously with epicarp
; hard; not splitting into 1-seeded pyrenes; without operculumoperculum:
a dehiscent cap (or lid) of a seed or fruit that opens during germination or dehiscence
; without secretory cavities; without longitudinallongitudinal:
of or relating to length or the lengthwise dimension
ridges. Funiculusfuniculus:
(alt. funicle) stalk connecting the ovule (later seed) to the ovary (later fruit) placenta
short; short without seed bearing hookswith hooks:
bristles or spines with curved or backwards pointing tips, or with secondary bristles along their length
(retinacula); not persisting in fruit after seed shed.

Seeds: Arilaril:
(broad sense) appendicular structure that wholly or partly envelops a seed and is produced from or a modification of the funicle, raphe, or outer integument; usually fleshy or pulpy, sometimes spongy or tufted-capillate, often brightly colored
absent. Seed not bowl shaped; not nutlike; without winglike beakbeak:
a usually firm, terminal appendage, sometimes tapered
; without caudatecaudate:
tapering to a long, tail-like appendage
appendage(s); at maturity with food reserves; with endosperm; without canavanine. Sarcotestasarcotesta:
pulpy or fleshy outer layer of the seed coat, simulates aril
absent. Testatesta:
seed coat
present; without markedly different marginalmarginal:
at, on, or close to the margin or border
tissue; without fleshy or leatheryleathery:
texture—moderately thick, tough, and very pliable
layer over hard layer; without crease or line separating cotyledons from hypocotyl-radicle; without notch along margin where cotyledons from hypocotyl-radicle tip approach each other; without glands; without bristles; glabrousglabrous:
without hairs
; without wings; without collar; without operculumoperculum:
a dehiscent cap (or lid) of a seed or fruit that opens during germination or dehiscence
; colored; monochrome; not becoming mucilaginousmucilaginous:
resembling mucilage; moist and sticky
when wetted; surrounding food reserve. Endosperm copious; hard; smooth; without fatty acid containing cyclopropene; without apicalapical:
at or pertaining to the end of the seed or fruit distal from its point of attachment (i.e., base)
lobes; without chlorophyll; without isodiametric faceted surface; without odor. Embryo differentiated from food reserve; well developed; 1 per seed; partially filling testatesta:
seed coat
(with food reserve); 0.3 times the length of food reserve; at one end of seed not extending into a depression or cup; laterallateral:
(of embryo) embryo lies along the side of the seed, generally towards one end; of, at, or from the side; in grasses, can refer to the sides adjacent to the dorsal and ventral sides
; linearlinear:
(shape) long, narrow, and uniform in width; (of embryo) embryo is straight and much longer than wide
(or nearly so); straight; lying along one side of endosperm; with cotyledons gradually connected to hypocotyl-radicle; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; well developed; 0.5 times length of embryo; as wide as hypocotyl-radicle (or nearly so); 1.2 times wider than hypocotyl-radicle; not concealing hypocotyl-radicle; not foliaceous; thin; flat; smooth; with apicesapex:
the point farthest from the point of attachment, or the "tip" of an organ
entire; with margins separate; basally entire; equal in size; not punctatepunctate:
surface relief—dotted with pits or with translucent, sunken glands or with colored dots, similar to pitted
dotted. Hypocotyl-radicle well developed; straight; not thickened.

Distribution

General distribution: New World.

Detailed distribution: South America (tropical).

Notes

From text with Hooker [2441]: Dr. Warburg, in Engler & Prantl, (Flacourtiaceae 54) described it as one-seeded, the seed exabuminous and the embryo curved…" and this is where Airy Shaw got these characters which here are rejected. Hooker made it clear that the "disk surrounds mature fruit". Cronquist: "ovary half sunken into disk".
 

References

Literature specific to this family: Sandwith, N.Y. 1962. Contributions to the flora of tropical America: LXIX. A new genus of Peridiscaceae. Kew Bull. 15:467–471; Hooker, W.J. 1896. Peridiscus lucidus Benth. Icon. pl. 23: pl. 2441.

General references: Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Engler, A. & K. Prantl. 1924 and onward. Die Natürlichen Pflanzenfamilimien. W. Engelman, Leipzig, Goldberg, A. 1986 (dicots) & 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) & 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gunn, C.R., J.H. Wiersema, C.A. Ritchie, & J.H. Kirkbride, Jr. 1992 & amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, Hooker, J.D. 1873 and forward. Icones Plantarum. William & Norgate, London. (plate number cited in text within [ ]), and Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.