Desmanthus Willd., Sp. Pl. 4: 1044. 1806.

Bruneau, Anne, de Queiroz, Luciano Paganucci, Ringelberg, Jens J., Borges, Leonardo M., Bortoluzzi, Roseli Lopes da Costa, Brown, Gillian K., Cardoso, Domingos B. O. S., Clark, Ruth P., Conceicao, Adilva de Souza, Cota, Matheus Martins Teixeira, Demeulenaere, Else, de Stefano, Rodrigo Duno, Ebinger, John E., Ferm, Julia, Fonseca-Cortes, Andres, Gagnon, Edeline, Grether, Rosaura, Guerra, Ethiene, Haston, Elspeth, Herendeen, Patrick S., Hernandez, Hector M., Hopkins, Helen C. F., Huamantupa-Chuquimaco, Isau, Hughes, Colin E., Ickert-Bond, Stefanie M., Iganci, Joao, Koenen, Erik J. M., Lewis, Gwilym P., de Lima, Haroldo Cavalcante, de Lima, Alexandre Gibau, Luckow, Melissa, Marazzi, Brigitte, Maslin, Bruce R., Morales, Matias, Morim, Marli Pires, Murphy, Daniel J., O'Donnell, Shawn A., Oliveira, Filipe Gomes, Oliveira, Ana Carla da Silva, Rando, Juliana Gastaldello, Ribeiro, Petala Gomes, Ribeiro, Carolina Lima, Santos, Felipe da Silva, Seigler, David S., da Silva, Guilherme Sousa, Simon, Marcelo F., Soares, Marcos Vinicius Batista & Terra, Vanessa, 2024, Advances in Legume Systematics 14. Classification of Caesalpinioideae. Part 2: Higher-level classification, PhytoKeys 240, pp. 1-552 : 1

Desmanthus Willd., Sp. Pl. 4: 1044. 1806.

Figs 144 , 145 , 146 , 153

Acuan Medik., Theodora: 63. 1786, nom. rej. vs. Desmanthus Willd. Type: Acuan virgatum (L.) Medikus [(≡ Desmanthus virgatus (L.) Willd.)]

Darlingtonia DC., Ann. Sci. Nat. (Paris) 4: 97. 1825. Type: Darlingtonia brachyloba (Willd.) DC. [≡ Acacia brachyloba Willd. (≡ Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. & Fernald)]

Type.

Desmanthus virgatus (L.) Willd. [≡ Mimosa virgata L.]

Description.

Unarmed, mostly woody shrubs or small trees to 4 m, or functionally herbaceous perennials much-branched from a woody base (Fig. 144F, G ), arising from a stout cylindrical or napiform tap root and dying back annually to the base in temperate regions, brachyblasts present in woody species. Stipules usually persistent, setiform with a dilated, auriculate base. Leaves bipinnate, extrafloral nectaries between proximal pair of pinnae and sometimes other pinnae pairs; pinnae 1-9 (17) pairs, opposite; leaflets 5-45 (55) pairs per pinna, opposite, variable in size and shape (linear, oblong, elliptic). Inflorescences capitate, peduncle sometimes with a distal involucel of united bracts, 1 (2) in leaf axils, composed of variable proportions of sterile, functionally staminate, and hermaphrodite flowers, rarely all of one type (Fig. 145F ); bracteoles subtending each flower deltate, peltate. Flowers with sepals valvate in bud, petals valvate; sterile flowers borne proximally, with elongated showy white, or rarely pink, filamentous staminodia (Fig. 145F ), ovary vestigial but like the fertile flowers in other respects; fertile flowers with the calyx cupulate, 5-lobed; petals 5, free, white or pale green; stamens 10 (5 in one species), filaments white or pink, anthers glabrous, lacking an apical gland; pollen in symmetric tricolporate monads, the exine striate, fossulate or foveolate; ovary sessile, glabrous or rarely pubescent, stigma funnelform. Fruits linear, flattened, valves chartaceous or coriaceous, seeds oblique or longitudinal, inertly dehiscent along both sutures (Fig. 146E ) (indehiscent in one species). Seeds ovate to rhomboidal, pleurogram U-shaped.

Chromosome number.

2 n = 28 ( Turner and Beaman 1953).

Included species and geographic distribution.

23 species. Three endemic species in the USA, with six extending to Mexico, six endemic species in Mexico, with three species extending to South and Central America, one endemic to Argentina, two bicentric in the USA and Argentina, one in the Antilles and north-western South America, one widespread USA to Argentina (Fig. 153 ). One species, Desmanthus pernambucanus (L.) Thell. (often mis-identified as D. virgatus ), is weedy and widely introduced throughout the tropics.

Ecology.

Seasonally dry tropical forest and semi-arid thorn scrub (ca. 10 species); warm temperate scrubland and oak woodland (seven species), three species extending to cool temperate grasslands and woodlands, two species in wet tropics (but absent from the Amazon basin), very often in disturbed open habitats, abandoned pastures and coastal thickets. Seed dispersal passive. Usually deciduous. Nodulating, symbiosome present. Bee-pollinated ( Xylocopa and generalist bee species).

Etymology.

From Greek, desme (= bundle) and anthos (= flower), in reference to dense capitate inflorescences.

Human uses.

Used as ornamentals, livestock fodder and in erosion control; Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. & Fernald is used for food (leaves, cooked seeds), medicine and is a potential pulse crop ( Luckow 1993).

Notes.

The delimitation of Desmanthus was altered by Hughes et al. (2022b) to account for the non-monophyly of the genus and exclude the morphologically and phylogenetically distinct species Desmanthus balsensis , which was placed in the new genus Mezcala .

Taxonomic references.

Luckow (1993), including illustrations; Luckow et al. (2003, 2005).

Figures

Figure 144. Habit and growth forms of genera of the Dichrostachys clade A herbaceous to weakly woody thicket of shrubby Neptunia plena (L.) Benth. in seasonally inundated ruderal habitat, Bolivia (Saerkinen 2159) B, C medium-sized to large trees of Lemurodendron capuronii Villiers & P. Guinet, north-western Madagascar (Koenen 429) D small tree of Leucaena matudae (Zarate) C. E. Hughes in seasonally dry tropical forest, Guerrero, Mexico (Hughes 2153) E shrub of Kanaloa kahoolawensis Lorence & K. R. Wood cultivated, National Tropical Botanical Garden, Kaua'i, Hawaii F small treelet of Desmanthus fruticosus Rose, Baja California, Mexico (Hughes 1532) G prostrate woody suffrutex of Desmanthus acuminatus Benth., Potosi, Bolivia (Hughes 2314) H shrub of Mimozyganthus carinatus (Griseb.) Burkart, Santa Cruz, Bolivia (Hughes 2476) I shrub of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart, Mendoza, Argentina J shrublet of Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet, Puebla, Mexico (Hughes 1784) K small treelet of Dichrostachys cinerea (L.) Wight & Arn., Kruger National Park, South Africa L small treelet of Alantsilodendron pilosum Villiers, S. Madagascar (Luckow 4162) M treelet of Gagnebina pterocarpa (Lam.) Baill., Madagascar N shrub of Dichrostachys venosa Villiers, in dry spiny forest, southern Madagascar. Photo credits A, D-H, J CE Hughes B, C E Koenen I Estepa Patagonica K B Dupont L M Luckow M C Commenge naturetropicale N D Du Puy.

Figure 145. Inflorescences and flowers of genera of the Dichrostachys clade A Lemurodendron capuronii Villiers & P. Guinet (Koenen 435) B inflorescence of Neptunia plena (L.) Benth., basal flowers sterile with showy yellow petaloid staminodia (Wood 26650) C inflorescence of Leucaena esculenta (Sesse & Mocino ex DC.) Benth. (Hughes 1326) D inflorescences and tergeminate leaves of Kanaloa kahoolawensis Lorence & K. R. Wood E fascicles of capitate inflorescences in axils of coevally developing leaves, Schleinitzia fosbergii Nevling & Niezgoda F inflorescences of Desmanthus bicornutus S. Watson showing basal sterile flowers with exserted white showy staminodia (Hughes 1526) G capitate inflorescences of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart H semi-spherical capitate inflorescences of Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet (Hughes 1784) I inflorescence of Alantsilodendron ramosum Villiers J spicate inflorescences of Gagnebina pterocarpa (Lam.) Baill., the basal flowers sterile with showy white staminodia K spicate inflorescence of Dichrostachys cinerea (L.) Wight & Arn., basal flowers sterile with showy pink staminodia L compact spikes of Dichrostachys akataensis Villiers the basal flowers sterile with showy pale pink staminodia. Photo credits A E Koenen B, C, F, H, J, K CE Hughes D A Palomino E Lauren Gutierrez G D Cabral, Flora Mondocina I, L D Du Puy.

Figure 146. Fruits of genera of the Dichrostachys clade A leaves and pod of Lemurodendron capuronii Villiers & P. Guinet, north-eastern Madagascar (Koenen 429) B Neptunia plena (L.) Benth. fruits dehiscing along the dorsal suture (Wood 26650) C ripe pods of Leucaena cruziana Britton & Rose, Oaxaca, Mexico (Hughes 1300) D cluster of unripe pods on a single inflorescence of Leucaena leucocephala (Lam.) de Wit subsp. glabrata (Rose) S. Zarate, Honduras (Hughes 1557) E ripe pods of Desmanthus leptophyllus Kunth dehiscing along both sutures (Hughes 3098) F unripe fruit of Mezcala balsensis (J. L. Contr.) C. E. Hughes & J. L. Contr., held erect, Guerrero, Mexico G ripe fruits of Mezcala balsensis dehiscing from the apex along both sutures H, I unripe and ripe fruits of Kanaloa kahoolawensis Lorence & K. R. Wood, cultivated at the Olinda rare plant propagation facility, Maui, Hawaii, USA J ripe fruits of Schleinitzia insularum (Guilemin) Burkart, the valves tardily splitting along both sutures but indehiscent K winged fruits of Gagnebina pterocarpa (Lam.) Baill., Madagascar L unripe, lomentiform fruits of Prosopidastrum globosum (Gillies ex Hook. & Arn.) Burkart which break up into one- or few-seeded fragments when ripe M ripe fruits of Mimozyganthus carinatus (Griseb.) Burkart, S Bolivia (Hughes 2476) N ripe fruits, elastically dehisced from the apex, Calliandropsis nervosa (Britton & Rose) H. M. Hern. & P. Guinet, Puebla, Mexico (Hughes 1784) O unripe coiled fruits of Dichrostachys cinerea (L.) Wight & Arn. P ripe fruits dehiscing elastically from the apex, Dichrostachys venosa Villiers, southern Madagascar Q ripe fruits of Alantsilodendron pilosum Villiers, Madagascar. Photo credits A E Koenen B-E, M, N C Hughes F, G J Luis Contreras H, I A Palomino J G McCormack, Cook Islands Biodiversity K, P, Q D Du Puy L I Specogno, Flora Mendocina O Atamari (CC-BY-SA- 3.0).

Figure 153. Distribution of Desmanthus based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.