Monographs Details: Calliandra macqueenii Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1998. Silk tree, guanacaste, monkey's earring: A generic system for the synandrous Mimosaceae of the Americas. Part III. Calliandra. Mem. New York Bot. Gard. 74: 1-223.
Description:Species Description - Macrophyll bushy shrubs 1-1.5 m with smooth gray-brown branches, the young shoots and both faces of lfts ± pilosulous with spreading and narrowly ascending hairs to ±0.5 mm, the dull olivaceous sub-concolorous lfts densely papillate, the dense capitula of pale-pink ochroleucous-stamened fls shortly pedunculate from axillary brachyblasts; phyllotaxy distichous. Stipules firm-papery, narrowly lanceolate or ovate-lanceolate 3-9 x 0.8-1.3 mm, 5-8-nerved, becoming dry and brittle. Lf-formula i/2; lf-stks 9-21 mm, at middle ±0.5-0.7 mm diam, shallowly openly sulcate ventrally; rachis of pinnae 10-21 mm, the smaller proximal pair of lfts inserted well below middle; lft-pulvinules 0.7-1 x 0.55-0.7 mm, finely wrinkled; lfts inequilaterally elliptic or obovate-elliptic from semicordate base, deltate- or triangular-apiculate, the blade of distal pair 2.2-5 x 0.9-2.2 cm; venation palmate-pinnate, the gently incurved midrib displaced to divide blade ±1:2, 5-8-branched on each side, the strong inner posterior primary nerve produced beyond mid-blade. Peduncles stout 2.5-5 mm, sometimes bracteate; capitula ±20-40-fld, the receptacle 5-7 mm; bracts lanceolate or ovate, <1 mm, persistent; perianth 4- or 5-merous, the calyx sharply finely striate, the membranous corolla faintly striate below middle, thereafter swollen, externally veinless, both calyx and corolla thinly pilosulous, especially distally; calyx campanulate 1.9-2.3 x 1.2-1.6 mm, the teeth 0.3-0.5 mm; corolla ±9-10 mm, the obtuse lobes ovate ±2 mm; androecium ochroleucous 18-20-merous, ±4 cm, the stemonozone 0.7 mm, the tube 15-16 mm, well exserted, no intrastaminal nectary seen; ovary at anthesis glabrous. Pods apparently erect from branchlets, subfalcately linear-oblanceo- late in profile, (6-)8-14 x 0.65-0.8 cm, the sutural ribs ±1.5 mm wide in dorsal view, the thinly lignescent valves finely thinly pilosulous overall, faintly venulose; seeds (few seen) in profile oblong ±10 x 5 mm, the hard smooth testa brown darker-speckled, pleurogrammic.

Distribution and Ecology - In brush-woodland near 130 m, known only through the type-collection, from hill country on the Mexico City highway ±15 km n. of Acapulco (17°01'N, 99°47'W), Guerrero, Mexico. — Fl. I—III.

Relationships - Calliandra macqueenii is presumably a recent derivative of C. tergemina var. emarginata, with which it has much in common, but differs substantially in too many details to escape formal description. As listed in the Latin diagnosis, the principal differential characters include the following: shortly pedunculate capitula of some 20 to 40 flowers crowded along a distinctly elongate receptacle; an extremely long, far-exserted staminal tube; and pods stiffly erect on lignescent peduncles. The species is dedicated to D. J. Macqueen (OXF), who has recently amassed an extensive herbarium of Mexican and Central American Calliandra of all types but in particular of species akin to C. houstoniana, an important set of which has been presented to NY.

Distribution:Guerrero Mexico North America|