Retama

Taxonomy

Retama C.S. Rafinesque-Schmaltz Nom. cons. Sylva Tell. 22. Oct-Dec 1838.

Subfamily: Faboideae.
Phylogenetic Number: 3.30.21.
Tribe: Genisteae.
Species Studied - Species in Genus: 4 studied; 4 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
; unilocular; 0.7–2 cm long; 0.6–1 cm wide; 0.45–1 cm thick; length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical, or symmetrical; ovate to elliptic, or elliptic to ovate; with 1 straight and 1 curved suture, or both sutures parallelly curved; widest near middle or D-shaped; not inflated; terete; without beak, or with beak; declined; with solid beak the same color and texture as fruit; rounded at apex; oblique with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; nonstipitate; indehiscent (to finally incompletely dehiscent along vertical suture), or with all layers dehiscing; splitting along suture(s). Dehiscence of valves along 1 suture; probably apical and down; passive. Replum invisible. Epicarp glossy, or dull; monochrome (though some with darker areas); brown to dark or dark reddish brown, or tan; with surface texture uniform; glabrous; eglandular; without spines; not smooth, or smooth; with elevated features; not veined; not tuberculate; rugose, or wrinkled; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thick, or thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid (tan), or vitriol (dark reddish-brown); ligneous (or subligneous). Endocarp present; visible; dull, or glossy; opaque; monochrome (to darker and lighter when underlain by dark mesocarp); brown, or tan; spongy and cobwebby; without adhering pieces of testa; subseptate, or nonseptate; with septa thin (tissue paper-like), flexible, or thicker than paper, firm; with septa eglandular; coriaceous; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1(–2); length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; thick; straight. Aril absent.

Seed: 6–7.5 mm long; 4–5.5 mm wide; 3–4.5 mm thick; not overgrown; not angular, or angular; asymmetrical, or symmetrical; oblong, or reniform, or triangular (more or less), or D-shaped, or irregular; compressed, or terete, or mounded on 1 side and straight on other side; with surface smooth; without visible radicle and cotyledon lobes; 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, or partially adhering to endocarp; free from endocarp; dull; not modified by a bloom; colored; monochrome, or mottled; with frequent mottles, or infrequent mottles; dark reddish to greenish brown, or tan (to greenish or reddish tan), or green (light to dark), or black; with black overlay; glabrous; smooth; osseous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim present. 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; 0.3–1 mm long; with straight outline; oblong; marginal according to radicle tip; recessed; within rim; rim color of testa, or lighter than testa. Lens discernible, or not discernible; 0.5–2.5 mm long; with margins straight, or curved; linear, or oblong, or wedge-shaped; oblong, or circular (with a small satellite); not in groove of raphe; confluent with hilum, or adjacent to hilum; 0.1–0.3 mm from hilum; flush, or recessed; similar color as testa, or dissimilar color from testa; lighter than testa, or darker than testa; reddish brown, or tan, or black; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. 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; 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; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Mediterranean region, Northern Africa, Canary Islands, and Asia (Middle East).

Old World; southern Europe, or Mediterranean, or Southwest Asia, or Africa (northwest and north and Canary Islands), or Macaronesia.

Generic Notes

This genus is presented under the name Lygos M. Adanson in Heywood (1968).

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.