Cycadaceae

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

Cycadaceae C. Persoon

Common name: Cycad Family.

Number of genera: 1 genus.

Number of species (Mabberley 1997): 20 species.

Disseminule

Cone, or seed.

Description

Cones: Dry; strobilus when dry (Spjut Fig. 51A-B & only family); globoseglobose:
3D shape—more or less spherical
; symmetrical; with sporophylls; with frondlike sporophylls.

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 larger than minute; 25 to less than 50 mm long to 50+ mm long; 30–60 mm long; ellipsoidellipsoid:
3D shape—elliptic
, or circularcircular:
(of embryo) linear embryo is curved into an "O" shape
; in transectiontransection:
a cross section; representing a plane made by cutting across an organ at a right angle to its length
tereteterete:
approximately circular in cross section; width and thickness approximately equal
; 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 endospermendosperm:
nutritive starch- and oil-containing tissue present in many seeds
; without canavanine. Sarcotestasarcotesta:
pulpy or fleshy outer layer of the seed coat, simulates aril
absent. Testatesta:
seed coat
present; with fleshyfleshy:
texture—fairly firm and dense, juicy or at least moist, and easily cut
or leatheryleathery:
texture—moderately thick, tough, and very pliable
layer over hard layer (& over corkycorky:
firm, relatively light, discontinuous but strongly cohesive, and resilient
& bouyant layer); tight; dulldull:
reflecting only a low proportion of incident light, with no apparent sheen
; surface smooth, or unsmooth; surface with merged raised features; surface wrinkledwrinkled:
surface relief—shallow, irregular folds and furrows covering the surface; appearing overall though crumpled and then spread out
; 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; red (dish-brown), or brown (all shades), or yellow, or cream; not becoming mucilaginousmucilaginous:
resembling mucilage; moist and sticky
when wetted. Endospermendosperm:
nutritive starch- and oil-containing tissue present in many seeds
copious, or moderate; opaqueopaque:
not transmitting light
; 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); 0.7 times the length of food reserve; at one end of seed not extending into a depression or cup; axileaxile:
on or of the axis
and centric; foliatefoliate:
appearing leaf-like
; with more or less spatulatespatulate:
2D shape—like a spatula; rounded at the apex, with base long and tapered; (of embryo) embryo is straight and axile and centric with the cotyledons expanded to form the shape of a spatula or spoon; (of cotyledons) cotyledons expanded and wider than the stalk but not invested into the stalk
cotyledons; straight; parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; well developed; 0.3–0.9 times length of embryo; somewhat to significantly wider than hypocotyl-radicle; 1 times wider than hypocotyl-radicle (or a little more); smooth; with apicesapex:
the point farthest from the point of attachment, or the "tip" of an organ
entire; with margins adhering (usually at tips), or separate; basally entire; unequal 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, or moderately developed; straight; not thickened.

Distribution

General distribution: Old World.

Detailed distribution: Madagascar Africa and Asia Southeastern (to Indomalaysia).

Notes

LeMaout & Decaisne: "presenting several openings corresponding to the embryonic vesicles, from which descend folded cords terminated by embryos of which one only is developed". Seed multiembryonic and one only matures.

References

Literature specific to this family: Miquel, F.A.W. 1845. Observationes de ovulo et embryonibus Cycadearum. Ann. Sci. Nat., Bot. sér. 3, 3:193–206, tab. 8 & 9.

General references: Engler, A. & K. Prantl. 1924 and onward. Die Natürlichen Pflanzenfamilimien. W. Engelman, Leipzig, Gunn, C.R. & J.V. Dennis. 1976. World guide to tropical drift seeds and fruits, 240 pp. The New York Times Book Co., New York, 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, LeMaout, E. & J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, & Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182, and Johnson, L.A.S. & K.L. Wilson. 1990. Cycadophytina/Cycadatae with the single living order Cycadales (Cycads). In: Kubitzki, K., ed., The families and genera of vascular plants, pp. 362–377. Springer-Verlag, Berlin.