Astragalus

Taxonomy

Astragalus C. Linnaeus Sp. Pl. 755. 1 Mai 1753.

Subfamily: Faboideae.
Phylogenetic Number: 3.16.15.
Tribe: Galegeae.
Subtribe: Astragalinae.
Species Studied - Species in Genus: 195 studied; ca. 2000 in genus.

Description

Fruit: A legume; unilocular, or bilocular (including semibilocular); 0.2–20 cm long; 0.15–6 cm wide; 0.1–3 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide, or length less than twice as long as width, or wider than long; with persistent androecial sheath, or deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx (rarely in Astragalus pelecinus (L.) Barneby); with calyx shorter than fruit, or equal in length to fruit, or longer than fruit (and calyx inflated or not); without orifice formed by curving of fruit or fruit segments, or with orifice formed by curving of fruit or fruit segments; straight, or curved (or slightly curved), or 0.5-coiled, or 1-coiled, or S-curved; not plicate (but occasionally irregularly bent in Astragalus pelecinus (L.) Barneby); not twisted; symmetrical, or asymmetrical; linear, or oblong, or elliptic, or circular, or didymous, or ovate, or C-shaped, or falcate; with both sutures parallelly curved, or both sutures unequally curved, or 1 straight and 1 curved suture; widest near middle or D-shaped; not inflated, or inflated; compressed, or terete, or subtriangular (to triangular), or quadrangular, or flattened (in Astragalus pelecinus (L.) Barneby); without beak, or with beak; straight, or declined, or coiled, or hooked; with solid beak the same color and texture as fruit; short tapered at apex, or tapered at apex, or long tapered at apex, or rounded at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; short tapered at base, or tapered at base, or long tapered at base, or rounded at base, or truncate at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous, or leathery, or membranous, or chartaceous, or ligneous, or drupaceous, or fleshy (when fresh); seed chambers externally invisible, or visible; seed chambers with the raised seed chambers not torulose; margin not constricted, or constricted (two species, A. shelkovnikovii A.A. Grossheim and A. pelecinus (L.) Barneby); margin constricted along both margins; margin without sulcus, or with sulcus (intrusion of dorsal or dorsal and ventral sutures); margin plain, or embellished; margin with fringe (of spines); wing(s) absent, or present (narrow); nonstipitate (or sessile on stipelike gynophore), or substipitate, or stipitate; with the stipe 0.1–35 mm long; with all layers dehiscing (valves may completely separate but because of the longitudinal walls which separate the 2 valves in bilocular legume, each half functioning as an "indehiscent fruit"), or indehiscent (fragile and usually inflated and easily fracturing); splitting along suture(s). Dehiscence of valves along 1 suture, or both sutures; apical and down, or basal and up; active, or passive; with valves reflexing (inflexed). Replum invisible. Epicarp dull; monochrome, or multicolored; mottled; brown to reddish or blackish brown, or tan (to purplish tan), or black, or green, or purple; with purple overlay, or red overlay, or brown overlay (purplish), or green overlay; mottling color combination constant; with mottling over seed chambers; with surface texture uniform; pubescent and indurate, or glabrous, or pubescent but soon deciduous (sometimes in Astragalus pelecinus (L.) Barneby); with hairs erect, or appressed; with 1 type of pubescence, or 2 types of pubescence; pilose, or puberulent, or tomentose, or velutinous, or villous, or sericeous; with pubescence gray, or black (to rusty), or golden (dull and dark); with gray and black hairs intermixed; with pubescence uniformly distributed; with simple hairs, or complex hairs (straight, straight or hooked at apex); with T-shaped hairs (malpighiaceous); pliable, or stiff; with hair bases plain, or swollen (somewhat); eglandular, or glandular; with glandular dots (reddish); without spines; not smooth, or smooth; with elevated features; veined (venation not ribbed to ribbed); reticulately veined, or transversely veined relative to fruit length, or transversely veined relative to fruit length and reticulately veined; not tuberculate; rugose (to reticulate), or verrucose-rugose, or wrinkled (irregularly to regularly or cross to lengthwise); not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present, or absent (or nearly so); thin, or trace; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; ligneous (or subligneous), or coriaceous, or chartaceous. Endocarp present; visible; dull, or glossy; opaque; monochrome; tan, or brown (reddish, in Astragalus pelecinus (L.) Barneby), or black (brownish, in the former Astracantha); smooth, or cobwebby, or fibrous, or smooth and cobwebby; without adhering pieces of testa; nonseptate (longitudinal separation between seed chambers making 2 loculi); chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; remaining fused to epicarp; without wings; entire. Seed(s) 1–21; length parallel with fruit length, or transverse to fruit length; neither overlapping nor touching, or touching, or overlapping; in 2 or more series, or 1 series. Funiculus 0.1–15 mm long; of 1 length only (and with or without hairs); filiform, or thick, or triangular; straight, or curved, or hooked. Aril present, or absent; dry; when dry rim-aril; entire; greenish or reddish brown, or tan, or white, or green.

Seed: 1–7 mm long; 0.8–5 mm wide; 0.1–2 mm thick; not overgrown, or overgrown, 1 seed filling entire fruit cavity (rarely); not angular, or angular (dented or not on faces); asymmetrical, or symmetrical (except hilum); mitaform, or oblong, or reniform, or rectangular, or rhombic, or triangular, or pyriform, or elliptic, or D-shaped, or cordate, or irregular; compressed; with surface smooth; without visible radicle and cotyledon lobes, or with 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, or lighter in color than testa; with deep hilar sinus, or with shallow hilar sinus, or 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, or glossy; not modified by a bloom; colored, or clear (sometimes, except for mottles, in Astragalus pelecinus (L.) Barneby); monochrome, or mottled, or mottled and streaked; with frequent mottles, or infrequent mottles; with frequent streaks, or infrequent streaks; brown to reddish to yellowish brown, or tan (to greenish tan), or cream, or green (yellowish), or olive, or orange, or yellow, or purple, or black; with black overlay, or purple overlay, or red overlay; glabrous; smooth (sometimes with a fine reticulate-colored pattern on smooth surface), or not smooth; with elevated features, or recessed features; rugose, or wrinkled (reticutely in Astragalus pelecinus (L.) Barneby); pitted with small separate pits, or concaved, or punctate (in Astragalus pelecinus (L.) Barneby); coriaceous, or chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible, or visible; from hilum to lens; not bifurcating; darker than testa; reddish brown to brown; flush, or raised. Hilum present; visible, or partially concealed, or fully concealed; concealed by wing, or radicle lobe, or funicular remnant; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform, or larger than punctiform; 0.1–0.5 mm long; with curved outline; circular; between cotyledon and radicle lobe; recessed (to slightly so), or flush; not within corona, halo, or rim, or within halo, or within rim; halo lighter than testa; rim color of testa. Lens discernible, or not discernible; 0.1–1 mm long; with margins straight, or curved; oblong, or linear, or triangular, or diamond-shaped; oblong, or elliptic, or 2 circular mounds separated by groove, or circular; not in groove of raphe; adjacent to hilum, or confluent with hilum; 0.1–0.3 mm from hilum; mounded, or flush; similar color as testa, or same color as testa, or dissimilar color from testa; darker than testa; brown, or tan (greenish); not within corona, halo, or rim. Endosperm present; thick, or thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo, or 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; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; tan, or brown (reddish), or yellow, or white; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed, or parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose (some almost 1/2 size of cotyledons); lobe tip straight, or curved, or hooked; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons, or 1/2 to nearly length of cotyledons. Plumule rudimentary, or moderately developed; glabrous.

Distribution

North America to South America (Patagonia), Europe, the Mediterranean region, Russia, temperate northern Africa, tropical Africa (mountains), the Iranian Plateau, northern India, China, and Japan.

New World and Old World; Alaska to Canada to United States to Mexico to Central America to South America (to Patagonia); Argentina and Peru; Europe to Mediterranean to Russia to Africa to Southwest Asia to Japan to India to Indochina to China to Korea to Macaronesia to Mongolia (Africa (northern and upland tropical) and a single species in Indo-China, Astragalus sinicus C. Linnaeus).
 

Generic Notes

Astragalus has more species than any other legume genus, probably more than 2,000 species, and more than most other genera regardless of family. There are a remarkable number of publications dealing with the species, and a few of the major ones include: North America, Barneby (1964) and Isely (1983, 1984, 1985, 1986); southern temperate South America, Johnston (1938, 1947); highlands of tropical Africa, Gillett (1963a); Iran, Maassoumi (1986, 1989); Russia, Gontscharov and Borisova (1946); Pakistan and Himalayas, Ali (1961). In addition Maassoumi, Podlech, and others have issued a series of more than 30 papers for the Near East. Several sections of Astragalus have been monographed: Section Acanthophace A.A. von Bunge and section Aegacantha A.A. von Bunge (Deml, 1972); section Alopecuroidei A.P. de Candolle (Becht, 1978); section Caprini A.P. de Candolle (Podlech, 1988); section Chlorostachys A.A. von Bunge, Phyllolobium A.A. von Bunge, and section Skythropos N.D. Simpson (Wenninger, 1991); section Chronopus A.A. von Bunge (Ott, 1978)); section Dasyphyllium A.A. von Bunge (Aytaç, 1997); section Eremophysa A.A. von Bunge and section Eremophysopsis N.F. Gontscharov (Podlech, 1993); section Herpocaulos A.A. von Bunge (Podlech, 1984); section Laxiflori C. Agerer-Kirchhoff (Agerer-Kirchhoff and Agerer, 1977); section Megalocystis A.A. von Bunge (Tietz and Zarre, 1994); section Platyglottis A.A. von Bunge (Podlech, 1990); section Sesamei A.P. de Candolle (Gazer, 1993); and section Theiochrus A.A. von Bunge (Podlech and Kozik, 1983). Sanderson and Liston (1995) cladistically analyzed the Galegeae genera using molecular data. They concluded that Astragalus is monophyletic with Astracantha Podlech (16.16) nested within it and that Astracantha should be included in it, possibly as a subgenus. Zarre and Podlech (1997), using morphological and anatomical data, concurred that Podlech's Astracantha should not be maintained as a genus. They concluded that it should be synonymized with Astragalus and that it can not be maintained even at subgeneric level. Since Podlech erected the genus Astracantha and synonymized it, we have chosen to follow his last decision. The genus Biserrula L. has been accepted in some floras (Gillett et al. 1971; Heywood and Ball 1986; Hansen and Sunding 1993), but has been synonymized with Astragalus by Barneby (1964) and Lock (1989). We have chosen to follow Barneby. Polhill (1994b) maintained Neodielsia H.A.T. Harms (16.18) as a genus, but Mabberley (1997) kept it as a synonym of Astragalus. We have chosen to follow Mabberley. Barneby (1964) and others, including Hutchinson (1964), noted that "an important feature of the Astragalus pod is the septum or longitudinal wall produced across the cavity from the dorsal suture." Because we have restricted the term septum to the transverse wall of a legume that separates seeds, we will not use septum in the Barneby et al. sense. We agree with Barneby that legumes endowed with a complete internal longitudinal wall are to be termed bilocular (replacing two-celled fruits of the literature). A partial walled cavity is termed semibilocular, and a pod lacking this wall is unilocular. Barneby has a detailed discussion of Astragalus fruits.

 

Tribal Notes

Tribe Galegeae

 Traditionally this tribe has been called Galegeae. Reveal (1997) reported that the name Astragaleae was published before the name Galegeae. 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 Astragaleae. In 1999 Reveal (1999) reversed himself, so that this tribe remains the Galegeae. Welsh (1960) reported on the Galegeae of north-central United States. Sanderson and Liston (1995) carried out cladistic analyses of Galegeae genera using molecular data. They concluded that Galegeae is paraphyletic having given rise to tribes Cicereae (20), Hedysareae (18), Trifolieae (21), and Fabeae (19), and therefore requiring a re-evaluation of the circumscription of Galegeae. Heenan (1995, 1998c), utilizing unpublished nuclear ribosomal DNA ITS data, concluded that "Carmichaelia (17.05) is nested within (the) 'Astragalean clade' of Galegeae" and is the sister group of Clianthus. He therefore supported the proposal of Sanderson and Wojciehowski (1996) that Carmichaelieae should not be recognized at tribal level, but rather included in Galegeae.