Cytisus

Taxonomy

Cytisus R.L. Desfontaines Nom. cons. Fl. Atl. 2: 139. Nov 1798.

Subfamily: Faboideae.
Phylogenetic Number: 3.30.15.
Tribe: Genisteae.
Species Studied - Species in Genus: 13 studied; 33 in genus.

Description

Fruit: A legume; unilocular; 1.2–7 cm long; 0.4–1.3 cm wide; 0.1–0.3 cm thick; 2–9 times longer than wide, or length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla, or persistent corolla; with various petals; with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; asymmetrical, or symmetrical; linear, or oblong, or ovate; with both sutures nearly straight; not inflated (more or less), or inflated; compressed, or flattened; without beak; short tapered at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous, or coriaceous; seed chambers externally invisible, or visible; seed chambers with the raised seed chambers not torulose; margin not constricted, or constricted; margin slightly constricted along both margins; margin without sulcus; margin plain; wing(s) absent; nonstipitate, or substipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; brown to dark reddish brown, or black; with surface texture uniform; pubescent and indurate, or pubescent but soon deciduous, or glabrous; with hairs erect, or appressed; with 1 type of pubescence, or 2 types of pubescence; villous (to restricted to sutures), or pilose, or tomentose; with pubescence gray, or brown, or golden; with long and short gray plain-tipped hairs; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; not veined, or veined; reticulately veined; not tuberculate; faintly wrinkled; not exfoliating, or exfoliating in part; without cracks, or with cracks; cracking oblique to fruit length; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; brown to blackish brown, or tan; smooth; without adhering pieces of testa; subseptate, or nonseptate; with septa composed of minute fringe of hairs; with septa eglandular; chartaceous; not exfoliating, or exfoliating in part; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 8–14; length transverse to fruit length, or oblique to fruit length, or parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–1 mm long; of 1 length only; triangular; straight, or curved. Aril present; fleshy, or dry; when fleshy cupshaped; entire; covering less than 1/2 of seed; when dry rim-aril; entire; brown to reddish brown, or tan (to reddish tan), or orange.

Seed: 3–5 mm long; 2–4.2 mm wide; 1.5–2.5 mm thick; not overgrown; not angular; asymmetrical; oblong, or ovate, or rectangular, or rhombic, or circular, or D-shaped; compressed; with surface smooth; with visible radicle and cotyledon lobes, or without visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes, or with external groove between radicle and cotyledon lobes; with external groove between radicle and cotyledon lobes same color as testa; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; dull; not modified by a bloom; colored; monochrome, or mottled and streaked; brown to blackish, reddish, or greenish brown, or tan (to greenish or reddish tan), or red, or orange, or olive, or green, or black; with tan overlay; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 0.5 mm long; with curved outline; circular; apical at apex of radicle tip and between cotyledon and radicle lobe, or subapical to radicle tip, or marginal according to radicle tip; recessed; within rim; rim color of testa, or darker than testa. Lens discernible; 0.5 mm long; with margins straight, or curved; oblong; oblong; not in groove of raphe; confluent with hilum; mounded; similar color as testa; darker than testa; reddish brown; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; not concealing radicle; split over radicle; with lobes; with the interface division terminating at base of radicle; without margins recessed; yellow, or tan; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose, or linear; lobe tip straight; deflexed and parallel to cotyledon length; centered between cotyledons; equaling length of cotyledons, or 1/2 to nearly length of cotyledons, or exceeding length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Europe, North Africa, Canary Islands, and Asia.

Old World; Europe to Mediterranean to Russia to Africa to Southwest Asia to India to China to Macaronesia (Africa (north, Canary Islands)).

Generic Notes

Talavera and Gibbs (1997) added two species to Cytisus, and the species count includes them. Polhill (1994b) accepted Lembotropis A.H.R Grisebach (30.16) as a genus, but we are maintaining it as a synonym of Cytisus.

Tribal Notes

Tribe Genisteae

Traditionally this tribe has been called Genisteae. Reveal (1997) reported that the name Cytiseae was published before the name Genisteae. Following the International Code of Botanical Nomenclature (Greuter et al., 1994), the oldest name for a taxon must be used, so Reveal suggested that this tribe should be called Cytiseae. In 1999 Reveal (1999) reversed himself, so that this tribe remains the Genisteae. Bisby (1981) summarized tribe Genisteae, following the excellent study by Polhill (1976). Bisby correctly noted that "many species have been moved from one genus to another several times and the Cytisus-Genista complex has gained a reputation as a critical group." He continued with an indepth analysis of the tribe. Polhill (1994a, 1994b) and Van Wyk and Schutte (1995a), using chemical and morphological characters, transferred five genera from Crotalarieae (27) to Genisteae: Anarthrophyllum (30.06), Argyrolobium (30.03), Dichilus (30.02), Melolobium, and Sellocharis (30.07). Cristofolini (1997) carried out a cladistic study of the tribe's biogeography, and discussed its early evolutionary history. López et al. (2000) studied the species of this tribe occurring in southwestern Spain and presented detailed descriptions for and a key to them.