Salsola L.
Complex genus in which, despite the absence of a global taxonomic treatment, its species have been studied in depth from the morphological, physiological, anatomical, biochemical and molecular point of view. It has been suggested that this group should be considered more like a group of genera rather than as a monophyletic natural group (Hernandez-Ledesma et al., 2015. 342). Therefore, some databases consider valid genera such as Caroxylon Thunb., especially since the publication by Akhani et al. 2007, or Nitrosalsola Tzvelev, after Feodorova 2015, based on morphological and phylogenetic aspects. In various Floras and studies Salsola is maintained, including sections or subsections like Salsola, Darniella, Caroxylon, Vermiculatae, Tetragona, etc.
On the other hand, the great morphological variability of the species, already large even within the same species, is altered by the extreme environmental conditions in which they grow (salinity of the substrate, aridity that can be extreme); these environmental conditions apparently modify the plant’s appearance (leaf length, indumentum, inflorescences, etc.). For this reason, various authors argue for the validity of many taxa that have been described.
So the correct identification of the different species is not without serious problems given the great morphological similarity between them, making the status of many of them uncertain (Freitag, 1997; Klopper & Van Wyk, 2001; Mosyakin, 2003, Schutze et al. 2003). Thus, there are two points of view when defining a species: a synthesising approach, that defends the concept of mega species (Freitag, 1997), and an analytic approach, whose greatest exponent is the Russian botanist V. P. Botschantzev, who has proposed the concept of microspecies (Akhani et al. 2007).
In North Africa there are almost fifty species, most of them shrublets that barely exceed 1 m in height, rarely shrubs up to 2.5 m. They are distributed across most of the region.
In addition to the clearly autochthonous species discussed here, it is worth mentioning 2 more species:
S. genistoides Juss. ex Poir. (Caroxylon tamariscifolium Moq.), with curious general broom-like or spathaceous appearance; stems strongly striated with linear and usually long leaves, up to 25 mm, but in certain specimens can be very short (3-25 × 0.5-1 mm), promptly deciduous; inflorescence in a characteristic terminal panicle or spike. It grows on loamy, subsaline terrain, in arid and semiarid environments in SE Spain. It has been cited in Morocco, although there are doubts about its presence in the region.
S. paletzkiana Litv, shrub up to 4 m high, leaves filiform, narrow and very long (4-10 cm), alternate; flowers solitary in the leaf axil and fruit perianth up to 25 mm in diameter. It is native to Turkestan but it has been introduced and is now naturalised at least in several Algerian oasis.
Akhani, H., Edwards, G.E. & Roalson, E.H. 2007. Diversification of the old world Salsoleae s.l. (Chenopodiaceae): molecular phylogenetic analysis of nuclear and chloroplast data sets and a revised classification. Int. J. Plant Sci. 168 (6): 931–956.
Botschantzev, V.P. 1972. Species subsectionis Tetragona Botsch. sectionis Caroxylon (Thunb.) Fenzl generis Salsola L. Novosti Syst. Vyss. Rast. 9: 140-154.
Botschantzev, V.P. 1975. New species of Salsola. Bot. Zhurn. 60 (4): 498-505.
Botschantzev, V.P. 1975. Species subsectionis Vermiculatae Botsch. sectionis Caroxylon (Thunb.) Fenzl generis Salsola L. Novosti Syst. Vyss. Rast. 12: 160-194.
Brullo, S. 1982. Notes of the genus Salsola (Chenopodiaceae). Willdenovia 12: 241-247.
Feodorova T.A. 2015. New nomenclatural combinations in Nitrosalsola (Chenopodiaceae). Ukr. Bot. J. 72(5): 442–445.
Freitag, H. 1997. Salsola L., pp. 154-371. In: Rechinger, K.H. (ed.). Flora Iranica 172. Akademische Druck- U. Verlagsanstalt.
Hernández-Ledesma, P. et al. 2015. A taxonomic backbone for the global synthesis of species diversity in the angiosperm order Caryophyllales. Willdenowia 45: 281-383.
Padrón, M.A. 2012. Caracterización morfológica y genética de las especies arbustivas de los géneros Salsola L. y Suaeda Forssk. ex J.F. Gmel. en las Islas Canarias (Tesis doctoral. Universidad de La Laguna).
Key to species
1 Leaves long 1.2-2.5(3) cm 2
1 Leaves short, usually less than 1 cm, may reach 1.2 cm 12
2 Stems striated. Leaves deciduous. Broom-like appearance Salsola genistoides
2 Stems smooth, somewhat striated or fissured. Leaves persistent. Not broom-like 3
3 Leaves alternate, linear Salsola webbii
3 Leaves opposite, at least the lower leaves 4
4 Without staminoids. Leaves trigonous, decurrent. Without a nectariferous disc Salsola oppositifolia
4 With staminoids. Leaves cylindrical or clavate, with a pulvinusat the base with whitish hairs. Nectariferous disc well developed 5
5 Pulvina of leaves and bracts with abaxial, long, lanate, exserted, hairs; stamens exserted; flowers in groups of 3 to 10 in each axil 6
5 Pulvina of leaves and bracts with abaxial, short, lanate, not exserted hairs; stamens do not protrude from the perianth; flowers solitary or in groups of 2 to 3 in each axil 8
6 Perianth urceolate up to 2 mm long Salsola glomerata
6 Perianth globose to ovoid not more than 1.5 mm long 7
7 Perianth segments ovate, laciniate at the apex, up to 0.8 mm wide; bracteoles oblong-linear up to 3 mm long, usually fully herbaceousand with two short appendages at the base, staminoids retuse at the apex Salsola cyrenaica
7 Perianth segments elliptical, entire or slightly wavy at the apex, up to 1.5 mm wide; bracteoles ovate up to 2 mm long, obtuseand with a membranous margin towards the apex; staminoids with a roundedapex Salsola schweinfurthii
8 Leaves and bracts alternate; flowers in groups of 2-3 in each axil; perianth 1.2-1.5 mm long Salsola zygophylla
8 Leaves and bracts opposite, rarely alternate; flowers solitary; perianth more than 2 mm long 9
9 Perianth segments with a perpendicular dorsal keel, crescent shaped, in the lower half. Fruit perianth with unequal wings: two small onesup to 4 mm wide and three larger ones over 6-8 mm wide 10
9 Perianth segments with a perpendicular dorsal keel, in the superior central part, without a crescent shape. Fruit perianth with equal or subequal wings 11
10 Bracts globose or subglobose, same length or shorter than the perianth; bracteoles with a retuse apex; perianth cylindrical-urceolate Salsola gymnosmaschala
10 Bracts semicylindrical, apiculate, longer than the perianth; bracteoles acute, apiculate; perianth ovoid Salsola verticillata
11 11Flowers with perianth 3-3.5 mm long, bracteoles 3-5 mm long and stamens 2.5-3.5 mm long. Fruit perianth 10-15 mm indiameter, with wings up to 6 mm wide, widely overlapping with each other Salsola longifolia
11 Flowers with perianth less than 2 mm long, bracteoles 2-3 mm long and stamens 1.5-2 mm long. Fruit perianth 7-12 mm in diameter,with wings less than 4.5 mm wide, not overlapping with each other Salsola cruciata
12 Plants spinescent 13
12 Plants not spinescent 15
13 Plant with scarce indumentum, glabrescent, with scattered hairs, spinulose Salsola acanthoclada
13 Plants with well defined indumentum 14
14 Young leaves and leaf buds with soft indumentum of simple,soft, sessile hairs; staminoid appendages long and semicircular Salsola cyclophylla
14 Young leaves and leaf buds with rugged indumentum of medifixed, adpressed and rough hairs, staminoids without appendages Salsola spinescens
15 Leaves opposite, decussate, densely imbricate 16
15 Leaves alternate, imbricate or densely clustered in glomeruli 17
16 Plant usually decumbent. Leaves very imbricate giving the branchlets a cylindrical-subtetragonal appearance, with long internodes(3-6 mm). Perianth segments 4, 1.5-2 mm Salsola tetrandra
16 Plant erect. Branchlets with clearly tetragonal appearance, with shorterinternodes (1-2 mm). Perianth segments 5, 3-3.5 mm Salsola tetragona
17 Leaves 0.4-1.2 cm long, villous-yellowish with denticulate hairs, young branchlets with the same hairiness Salsola villosa
17 Leaves usually less than 0.4(0.5) cm long, if longer neithervillous-yellowish nor with denticulate hairs, pubescent or not 18
18 Leaves imbricate, fleshy, suborbicular and obtuse, up to 2-5 mm long. Fruit perianth with very short whitish wings, 3.5- 5.5 mm indiameter Salsola imbricata
18 Leaves not imbricate and grouped in glomeruli, fleshy or not, elongated (longer than wide), attenuate at the apex into an obtuse tip. Fruit perianthwith larger wings, usually more than 5 mm in diameter, whitish, reddish or purple 19
19 Plant glabrous. Leaves (5)8-12 mm long. Fruit more than 5 mmin diameter with membranous wings Salsola vermiculata
19 Plant pubescent. Leaves 3-5(7) mm long. Fruit less than 5 mm in diameter with scarious wings Salsola brevifolia
Updated by: G. Benítez & J. Molero Mesa.