TYPE: BRAZIL. Espirito Santo: Baixo Gandu. collected by W. Zaslawski and E. Colnago, flowered in cultivation March 1997, R. Kautsky 1053 (Holotype: HB). Fig. 10.
Inter generis species valde singularis, a speciebus omnibus follis manifeste numerosis et dense rosulatis, ramis pedunculis 35-40 cm longis. bracteas steriles 5-6, carinatas usque ecarinatas ornatis, racemis 17-22 x 7.5-8.5 cm (petalis exclusis), perdense 18-20 floridis, prope apicem teretiusculis sed per anthesim basin versus complanatis. sepalis late ovatis. petalis prope basin ligulis binis lobis suborbicularibus et truncato-crenulatis differt.
Plant lithophytic. flowering ca. 230 cm tall.
Leaves ca. 100, very densely rosulate, suberect to spreading, forming at base a broadly funnelform rosette;
Sheaths nor. completely known. castaneous;
Blades narrowly triangular. ca. 60 cm long, ca. 16 cm wide near the base, glabrescent, adaxially glaucous, abaxially green, on both sides very densely white-cretacoous mainly toward base. apex acuminate.
Scape ca. 60 cm long, 3-4.5 cm in diameter, stout, rigid;
Scape bracts the basal ones foliaceous, nearly erect and densely arranged.
Inflorescence laxly bipinnate-paniculate. ca. 110 cm long. 70-100 cm in diameter, subspreading but suberect neat the apex;
Primary bracts subtriangular, acute and apiculate, coarsely rugulose-sulcate after anthesis, ca. 5 x 3 cm, reddish, glabrescent, dlstinctly shorter than the sterile basal peduncle;
Branches ca. 30. subspreading but ascending near the apex, 52-62 cm long,
peduncle 35-40 cm long. 1.5-2 cm in diameter, stout. Bearing 5-6 sterile bracts carinate to ecarinate and erect,
Raceme 17-22 x 7.5-8.5 cm (excluding the petals), very densely 18 to 20-flowered. terete near the apex but complanate toward base at anthesis,
Rachis straight, glabrous, dark green, ca. 1.3 cm in diameter;
Floral bracts ovate, ca. 8 x 3.3 cm, apex narrowly obtuse-emarginate, concave and slightly gibbose near the base, sulcate-rugulose, carneous, ecarinate, the basal ones wine colored, the upper ones yellowish-green, very inconspicuously lepidote inside. Densely imbricate toward apex at anthesis but not completely imbricate near the apex after anthesis, equaling to slightly exceeding the sepals.
Flowers distichous, not secund, divergent, ca. 4.5 cm long (excluding the petals),
Pedicels stout, ca. 1 cm long, ca. 1.2 cm in diameter, dark green;
Sepals symmetrical, broadly ovate, narrowly obtuse, ca. 3.7 x 2.5 cm, inconspicuously lepidote inside, free, ecarinate, yellow toward apex;
Petals slightly asymmetrical, sublinear, apex obtuse-cucullate, 10.5-11 x 1.7 cm, white, free, recurved to reflexed at anthesios, flaccid, bearing 2 appendages at base. 1.2-1.4 x 0.4 cm, with lobes suborbicular, truncate-crenulate.
Stamens ca. 11 cm long;
anthers linear, ca. 1.6 cm long, obtuse, dorsifixed near the base;
stigma simple-erect, blades subspreading, ca. 0.4 cm long, white.
Eponymy: Alcantarea roberto-kautskyi confers honor on the great benefactor of natural reserves in Espirito Santo State, Roberto A. Kautsky. He lives in the municipality of Domingos Martins and has brought to scientific light countless discoveries and rediscoveries of botanical and animal species.
Alcantarea roberto-kautskyi has no apparent affinity to any other species in its genus. Its unique character is defined by its numerous and densely rosulate leaves, branches with basal peduncles 35 to 40 cm long, bearing 5 to 6, carinate or ecarinate sterile bracts, the fertile portion 17-22 x 7.5-8.5 cm (excluding the petals ), with 18 to 20 flowers very densely arranged. The fertile segment of the branches is somewhat terete near the apex, despite more complanate toward base at anthesis. Also, this new species, with rupicolous habit on bare rocks at about 500 m of altitude, has broadly ovate sepals. and petals bearing appendages with suborbiculate and truncate-crenulate blades.