Painteria elachistophylla

  • Title

    Painteria elachistophylla

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Painteria elachistophylla (A.Gray ex S.Watson) Britton & Rose

  • Description

    2. Painteria elachistophylla (S. Watson) Britton & Rose, N. Amer. Fl. 23: 36. 1928 “elachisthophylla”. 1928. Pithecolobium elachistophyllum A. Gray ex S.Watson, Proc. Amer. Acad. Arts 17: 352. 1882. —“At Monterey, Nuevo León, ([E. Palmer] 289 [in Feb. 1880]).” — Holotypus, GH!; isotypus, NY!.

    Pithecolobium compactum Rose, Contr. U.S. Natl. Herb. 8: 33. 1903. — “Collected by J. N. Rose on the flat plain west of Tehuacan, Puebla [Mexico], August 1, 1901 (no. 5840).”— Holotypus, US!; clastotypus (fragm.), NY!. — Painteria compacta (Rose) Britton & Rose, N. Amer. Fl. 23: 36. 1928.

    Pithecolobium purpusii T. S. Brandegee, Univ. Calif. Publ. Bot. 4: 85. 1910. — “[Mexico. Puebla:] . . . near Tlacuiloltepec [7000-8000 ft, Jun-Jul. 1907, C. A. Purpus] No. 3869.”— Holotypus, UC 137969!, isotypus, NY!. — Equated with Painteria compacta by Britton & Rose, 1928: 36.

    Pithecollobium elastichophyllum [sic] sensu Standley, 1922: 395; Estrada & Marroquín de la Fuente, 1992: 71, fig. 20. Pithecollobium compactum sensu Standley, 1922: 395.

    Stiffly branched microphyllous shrubs ±3-12(25) dm with pallid or fuscous, flexuous branches erratically armed at nodes with pairs of straight ascending, straight spreading, or rarely subrecurved spinescent stipules subtending primary lvs of long-shoots, most lvs fasciculate on hemispherical or short-cylindric scaley brachyblasts, the annotinous stems glabrate, the new branchlets and lf-stks puberulent or pilosulous with fine whitish hairs 0.1-0.3 mm, the firm olivaceous, scarcely bicolored lfts either thinly pilosulous on both faces, on lower face only, or glabrous except for minute cilia, the capitula or short spikes of dull reddish, white-stamened fls solitary or fasciculate on brachyblasts, either subsessile or very shortly pedunculate. Stipules of most primary lvs 2-6 mm, tapering to a fuscous vulnerant point, of some lvs conic and only 1-2 mm, those of brachyblasts acicular or stiffly subulate <1.5 mm. Lf-formula i(—ii)/3— 10(—12), the pinnae bijugate only in rare primary lvs; lf-stks 1.5—5(—9) mm, the petiole 1.5—3(—5) mm; a subsessile or shortly stipitate nectary at tip of petiole round, dimpled, 0.15-0.3 mm diam, in profile narrowly drum-shaped or obovoid 0.3-0.5 mm tall, no nectary at tip of pinnae; rachis of pinnae mostly (5-)6—15(—16) mm, in one example (Fryxell 3610, NY) to 30 mm, the longer interfoliolar segments 1.4-2.4(-3) mm; lft-pulvinules 0.15-0.3 x 0.2-0.3 mm, faintly wrinkled; lfts opposite, either subequilong except for often longer furthest pair, or a little decrescent proximally, the blade suborbicular or broadly oblong from shallowly semicordate base, broadly obtuse, the penultimate pair 1.7-6 x 1.3-3.3 mm, 1.1-1.8 times as long as wide; venation palmate, of 2-3(4) nerves from pulvinule, the straight or subsinuous midrib only a trifle forwardly displaced, produced to blade-apex or V-forked close below it, the inner posterior primary nerve incurved-ascending to anastomosis approximately at or a little beyond midblade, the whole venation usually immersed on upper face, bluntly prominulous beneath. Peduncles 0-3(7) mm; capitula ±14—26-fld, the receptacle 2-5(11) mm; bracts ovate acute 0.4-0.6 mm, persistent into anthesis; fls sessile, homomorphic, the calyx 5-7-, the corolla 4—5-mer- ous, the calyx minutely gray-puberulent in distal 1/3, the corolla only at tip of lobes; calyx campanulate or hemispherical 0.9-1.5 x 1—1.3 mm, the deltate, often unequal, more or less incurved teeth 0.1-0.35 mm; corolla narrowly vase-shaped 3.6-5.8 mm, the ascending, ovate lobes 1-1.8 x 0.7-1.2 mm; androecium 28-44- or in one example 68-70-merous, 9-12 mm, the stemonozone ±0.4 mm, the tube 3.4—5.6 mm, either shortly or not exserted, the callosities at base of tube at most 0.2 mm tall, often obscure or wanting; ovary in profile narrowly ellipsoid, either glabrous or minutely puberulent at anthesis, becoming densely puberulent after fertilization, the stipe 1.1-2.4 mm; style about as long as androecium, slightly dilated at stigma. Pods solitary, in profile undulately broad-linear, long-attenuate proximally into pseudostipe and stipe, abruptly cuspidate, (5.5—)7—11 x 1-1.4 cm, (4—)5-8(-10)-seeded, evenly recurved through ¼-½ or even one full circle, the sutures ±2-2.4 mm wide, not prominent, shallowly constricted between most seeds, the stiffly leathery nigrescent valves low-convex over each seed, densely minutely puberulent overall, scarcely venulose, in age (after dehiscence) randomly fissured; dehiscence inert, through both sutures; seeds (few seen) descending on straight funicle, plumply lentiform 9-10 mm diam in broad view, nearly half as thick, the pleurogram incomplete.

    On plains and hillsides in desert brush communities, mostly between 1400 and 2360 m but descending in Tamaulipas to unknown elevation in the Gulf lowlands, locally plentiful but of discontinuous range in NE Mexico: Chihuahuan Desert and W slope of Sa Madre Oriental in S Coahuila, N Zacatecas, Nuevo León and San Luis Potosí; E-centr. Tamaulipas (Rancho Loreto, 24°20'N); and dry interior valleys of states of Puebla (Tlacuilotepec; Tehuacán) and Oaxaca (distr. Teposcolula). — Map 44. — Fl. II-V(VIII).

    Painteria elachistophylla is known from disjunct, desert or desertic enclaves, and the leaflet-number and pubescence show some differentiation between populations. In the Chihuahuan Desert the leaflets are mostly 3-5 pairs per pinna and thinly pilosulous, at least on the lower face. In San Luis Potosí and Puebla the leaflets are 5-7, rarely 8 or randomly up to 12 pairs per pinna and glabrous except for cilia. These states correspond with P. elachistophylla and P. com- pacta as defined by Britton and Rose. In Nuevo León we find instances (e.g., Mueller 961, NY) of 6-7 pairs of pubescent leaflets and in Tamaulipas one (M. C. Johnston 10469, NY) of 3-4 pairs of glabrous leaflets. Britton and Rose assigned to their two species peduncles essentially none as opposed to very short, but we have not found this a useful differential character. An exceptionally robust plant from municipio Rayon, San Luis Potosí (Fryxell 3610, NY) has shortly but distinctly spiciform capitula.