Samanea tubulosa

Title

Samanea tubulosa

Authors

Rupert C. Barneby

Scientific Name

Samanea tubulosa (Benth.) Barneby & J.W.Grimes

Description

2. Samanea tubulosa (Bentham) Barneby & Grimes, comb. nov. Calliandra tubulosa Bentham, London J. Bot. 3: 101. 1844. — "Brazil: banks of the Rio San Francisco, near Villa Nova [NE Bahia], Gardner, n. 1280; Cuyaba [Mato Grosso, Riedel, commun.] Langsdorff." — Lectotypus, labeled by Bentham "Sierra Chapada [= Chapada dos Guimarães]. Riedel" accompanied by a ticket reading "1830, [no.] 22, Cuyaba. Hb. Mus. Petr[op.].," K(herb. bentham.)! = photo s.n., NY!; presumed isotypi, Riedel s.n. e Cuiabá, A!, NY! — Paratypus, Gardner 1280, K! = NY Neg. 2016 = probably S. inopinata (Harms) Barneby & Grimes.

Pithecolobium saman var. (ß) acutifolium Bentham in Martius, Fl. Bras. 15(2): 442. 1876 "acutifolia". — "Habitat in prov. Para prope Santarem: Spruce n. 671; in Peruvia prope Tarapoto: Spruce n. 4405." — Syntypi, K: 671 (fl.), herb, bentham.! = NY Neg. 2071!, 671 (fr), herb, bentham.! = NY Neg. 2018!, and 4405 (fr), herb. bentham.! K(herb. hooker.)!, NY!, no. 4450, NY!, P!.

Pithecolobium venosum Rusby, Mem. Torrey Bot. Club 6: 29. 1896. — "[Bolivia.] Between Guanai and Tipuani, Apr.-June, 1892 ([//. H. Rusby] 1392)." — Holotypus, NY!; isotypi, DS-CAS!, K!, MINN!, UC 946443!. Samanea saman sensu Bernardi, 1984: 192.

Macrophyllidious trees commonly 8-25 m but in relatively dry forest conditions only (2-)3-8 m tall, with trunk attaining (1—)2—10 dm dbh, fissured, light-colored, thick, spongy or often corky bark, and angulate branchlets, the young stems, all lf-axes and peduncles puberulent or pilosulous with pallid, either straight and spreading-ascending or shorter incumbent hairs to 0.15-0.5 mm, the foliage bicolored, the lfts dull olivaceous and minutely or remotely puberulent on upper face, on lower face paler and more densely pilosulous (especially along veins), the umbelliform capitula of greenish, sometimes pink- tinged flowers with long, distally pink filaments arising singly or 2-3-nate in the axil of coeval or quickly hysteranthous lvs, sometimes in early anthesis appearing terminally paniculate but quickly surpassed by adult foliage, the innovations of each year arising laterally from below the annotinous inflorescence. Stipules narrowly lanceolate 3-9 x 0.7-1.3 mm, pubescent like adjacent stem, deciduous with early expansion of the associated lf. Lf-formula iii-vi (—vii)/3—5(—6); lf-stks (7-)8-28 cm, the petiole (2—)2.5—8(—11) cm, at middle (1—)1.2—2.7 mm diam, the ventral groove continuous between pinna-pairs, the longer interpinnal segments (2-)2.5-7 cm; nectary near base (well below middle) of lf-stk and often almost adjacent to lf-pulvinus sessile, in vertical view either round or (commonly) elliptic (1.2-) 1.4-4 mm diam, either shallowly patelliform, or plane, or rarely low-convex, usually thick-rimmed, in profile ±0.20.4 mm tall; no nectary between any pinna-pair but smaller, shallow-cupular ones on pinna-rachises close below the furthest 1-2 or rarely between all lft-pairs; pinnae greatly accrescent distally, the rachis of furthest pair (4—)5—11 cm, the longer interfoliolar segments (1.1—)1.3—3(—3.6) cm; paraphyllidia at apex of pinna-pulvini linear caducous; lft-pulvinules (1—) 1.2— 2.2(-2.5) x 0.5-1 mm, not wrinkled; lfts strongly accrescent distally, obliquely oblong- or rhombic- obovate from inequilateral base, either broadly obtuse, or obtuse-apiculate, or contracted into a deltate- apiculate tip, the blades of penultimate pair (2.5-) 2.8-6 x (1.3—)1.4—3.8 cm, (1.4—) 1.5—2.2 times as long as wide, the furthest pair commonly yet larger and often proportionately broader; venation pinnate, the straight diagonal or more often gently incurved and slightly excentric midrib giving rise on each side to (5-)6-9(-10) major (and sometimes few random minor) incurved-ascending secondary nerves brochidodrome shortly within the plane margin, and these in turn to a reticulum of venules, the whole venation pallidly discolorous and prominulous on both faces of lft, more sharply so beneath. Peduncles 3—10.5(—15) cm; capitula ±12—20-fld, the axis including pedestal of terminal fl usually 1.5-4 mm but the pedestal itself sometimes elongate to 5 mm and an occasional fl downwardly displaced onto peduncle; interfloral bracts linear-oblanceolate (1.7—)2—7 x 0.25-1 mm; fls dimorphic, the peripheral ones pedicellate, the terminal one sessile, the perianth of all 5-merous (rare abnormalities) and densely silky-pilosulous externally, the vesture of the corolla usually paler and more lustrous than that of calyx; PERIPHERAL FLS: proximal pedicels (1.4-)1.7-5.5(-7) x 0.35-0.55 mm; calyx including hypanthium narrowly infundibuli- form 5-ribbed (4-)4.6-7.5(-8.5) x 1.5—2.7(—3) mm, the often unequal, ovate or obtusely deltate teeth 0.6-1.8(-2) mm; corolla 9.5-14.5 mm, the ovate or narrowly oblong, apically cucullate and fimbriolate lobes (2.6-)3-5.5(-6.5) mm; androecium (16-)22-30 (-36)-merous, 34-46 mm, the stemonozone 1.5-2.3 mm, the tube 5-9(-10) mm, the free filaments white or pallid proximally, deep rose, pink, or reddish purple distally; ovary sessile, linear-elliptic tapering into the style, densely silky-strigulose at anthesis, densely pilosulous following fertilization; TERMINAL FL: calyx 7-12 x (1.8-)2-3.4 mm; corolla (13.5-)14-22 mm. Pods l(-2) per capitulum, sessile, in profile broad-linear, straight or randomly bent (but not recurved or coiled) girdled by stout plane sutures 2.5-4 mm wide, when well fertilized (7-)10-18.5 x 1.2-1.8 x 0.9-1.3 cm, 20-31-seeded, the finely or minutely but often at least at first densely puberulent valves convex, consisting of thin fuscous exocarp, a broad layer of alveolar pulp (pitchlike when dry), and a dry crustaceous endocarp inwardly either impressed or produced to divide the cavity into 1-seeded locules, the fleshy valves becoming bluntly ridged lengthwise but not or only faintly depressed between seeds, when ripe transversely cracking (but not sulcate) toward sutures; seeds transverse on slender but compressed funicle, basifixed, plumply compressed-oblong-ellipsoid, in broad view 6.5-8.5 x 3.5-4.7 mm, the smooth hard testa fuscous-castaneous, the narrowly U-shaped pleurogram ±5-6.5 x 2-2.4 mm.

In seasonally dry, semideciduous or drought-deciduous forest and in savanna enclaves within wet evergreen forest, mostly below 500 m, but ascending in inter-Andean valleys of Peru to 600-950 m, and in the Bolivian Yungas to 1300-1800 m, discontinuously widespread around the W and SW periphery of the Amazon basin and in the upper Paraguai basin, in Peru, Brazil westward from the Tocantins, Bolivia, and Paraguay, and reappearing locally along the lower Amazon and its immediate tributaries in Pará, Brazil; one isolated station in Pacific Ecuador (estado Manabí, there sympatric with S. saman, perhaps introduced), cultivated in NE Argentina (Corrientes). — Map 35. — Fl. (IX-)X-II(-III), immediately following flush of new lvs, the fruit shed simultaneously or a little earlier. — Lluicho vaina, lluicho vainilla (Peru); burdão de velho (Acre); ichizozo, penoco (Bolivia); niño azote (Paraguay).

Samanea tubulosa, which as a native tree replaces S. saman in South America southward from the equator, is readily distinguished from it, when in flower, by the nectary at base of each leafstalk and by (sub)linear floral bracts. The leaflets of longer pinnae are usually fewer by one or two pairs, and all are puberulent rather than glabrous on the upper face. Differences between the fruits collected by Spruce at Tarapoto in Peru and those of the genuine saman from Caracas were noted by Bentham in his revision of Mimoseae (1875: 587). In Flora Brasiliensis he voiced the suspicion that more than one species lay concealed in his concept of Pithecolobium saman, but for lack of complete material he could go no further than describe Spruce’s plant as a var. acutifolia [sic], supposedly different in characters of foliage rather than fruit. He was unaware that he had earlier described the same taxon as Calliandra tubulosa. The protologue of C. tubulosa was derived from two flowering collections, almost certainly not conspecific: Riedel s.n. from Chapada dos Guimarães near Cuiabá in Mato Grosso; and Gardner 1280 from near the mouth of Río São Francisco in northern Bahia. The identity of Riedel’s plant is now firmly established by fruiting topotypes, but that of Gardner’s plant will remain ambiguous until we have confirmatory pods from the region of the type locality.

The known facts of geographical dispersal (cf. Maps 35 and 36) suggest that Gardner’s plant is in reality S. inopinata. Our lectotypification of C. tubulosa makes the epithet available and unavoidable for the widespread species described here and bypasses the enigmatic identity of Gardner 1280.

Samanea tubulosa and S. saman are allopatric, so far as known (cf. Maps 34 and 35), but were collected close together on the same day near Chone in Manabí, Ecuador, by L. Holm-Nielsen (nos. 27947 and 27918 respectively, both NY). Samanea saman is a well-known and presumably native element of seasonally dry forest in Pacific Ecuador, but S. tubulosa is, except for this one record, entirely trans-Andean. Its status in Ecuador requires observation.