Iryanthera juruensis Warb.

  • Authority

    Smith, Albert C. & Wodehouse, R. P. 1938. The American species of Myristicaceae. Brittonia. 2: 393-527. f. 1-9.

  • Family

    Myristicaceae

  • Scientific Name

    Iryanthera juruensis Warb.

  • Description

    Species Description - Tree up to 20 m. in height, the trunk slender; branchlets slender; petioles rugose, canaliculate, narrowly winged distally, 1-2 mm. in diameter, 6-15 mm. long, glabrous; leaf blades chartaceous or thin coriaceous, finely rugose or minutely papillose and usually dull on both surfaces, elliptic-obovate or obovate-oblong, 10-20 cm. long, 3-7 cm. broad, acute to subattenuate at base, obtusely short acuminate at apex, the costa raised above, the secondary nerves 10-17 per side, spreading, slightly impressed or faintly raised above, raised beneath, inconspicuously anastomosing near margin, the veinlets immersed; staminate infloreseences 2-9 cm. long, fasciculate-racemose (fascicles sometimes borne on minute lateral branches about 1 mm. long), uniformly minutely strigose, the peduncle short, the rachis sleinder, the fascicles alternate, 5-18 per inflorescence; flowers 3-7 per fascicle, the pedicels slender, up to 6 mm. long, bracteolate at summit (bracteole membranous, oblong, rounded at apex, one-sided, less than 1 mm. long); perianth earnose or thin earnose, often glabrescent, cupuliform, 2-3.5 mm. long (normal flowers sometimes associated with unusually large and often abnormal flowers up to 4 mm. long), 3 (rarely 4)-lobed more than one-half its total length, the lobes deltoid, subacute; androecium 0.8- 1.5 mm. long, the filament column carnose, conspicuously swollen at base, 0.6-1.1 mm. long, the anthers 0.3-0.5 mm. long, dorsally connate or divergent in the distal one-half, the connectives usually inconspicuous, sometimes slightly carnose and glandular; pistillate inflorescences aggregated on the old bark of trunk, branches, or defoliated branchlets, 4-9 cm. long, usually 3-6-branched from base, the branches spreading, stout, ferruginous-strigose, sometimes again branched; flowers densely aggregated in clusters of 15-40 at the swollen ends of branchlets or fasciculate in smaller clusters near the ends of branchlets, the pedicels up to 4 mm. long, the ovary subglobose or ellipsoid, the stigma subsessile; fruiting inflorescences slightly longer than the pistillate, the mature fruits usually 1-3 per branch of inflorescence, pedicellate (pedicels stout, 5-7 mm. long), transversely ellipsoid or subglobose, 13- 20 mm. long, 15-24 mm. broad, inconspicuously carinate (sometimes slightly impressed at the sutures), smooth at apex, the lateral extremi- ties rounded, the base flattened or obtuse, essentially estipitate, the pericarp rugose, 1-2 mm. thick, the aril inconspicuously laciniate in the distal one-third with broad lobes, the seed transversely ellipsoid or subglobose. (Fig. 5. a-i.)

  • Discussion

    Iryanthera grandiflora Huber, Bol. Mus. Goeldi 5: 358. 1909.

    Iryanthera densifora Huber, 13ol. Mus. Goeldi 6: 69. 1910.

    Iryanthera trigona Markgraf, Notizbl. Bot. Gart. Berlin 10: 237. 1928.

    Type locality: Upper Rio Jurua, Amazonas, Brazil.

    Native names: Peru: Cumala, Cumala, del alturas

    The fruit of I. juruensis shows considerable variation in shape, being from practically globose to distinctly ellipsoid. Collections of fruits intermediate in shape indicate that this difference cannot be used taxonomically. Krukoff 6449, in fact, has both kinds of fruit and many intermediate stages. This variation is unusual in Iryanthera, where as a rule the fruit shape is a dependable character. The fruit of I. juruensis may readily be recognized, however, by its plane or slightly impressed sutures, its rounded extremities, and its rugose pericarp of quite uniform thickness. These characters distinguish the fruit of this species from that of l. Ulei. The fruit of Krukoff 1298 was erroneously described by me1 as of I. Ulei. This species has a fruit with much sharper extremities and more obvious sutures. Ducke (6: 218) has maintained I. densiflora on the basis of its simple and dense inflorescences with relatively large flowers. These characters, however, do not separate the species from I. juruensis, and I fail to find any others which can be trusted. In reducing I. grandiflora to I. juruensis Ducke (6: 219) has already remarked that occasional large flowers are to be found in the inflorescences of this species. 1. grandiflora has the subglobose type of fruit mentioned above. This fruit is more commonly found on specimens from the Peruvian rivers, while those from the Jurua, Madeira, etc., as a rule have ellipsoid fruits. I have not been able to find characters on which the type of I. trigona can be separated from I. juruensis. This specimen has the staminate perianth slightly campanulate rather than strictly cupuliform and has the basal swelling of the filament column inconspicuous. These characters, however, appear to me not of taxonomic consequence, in view of the similarity of foliage.

  • Distribution

    Amazonian Brazil and Peru. PERU: Loreto: Rio Huallaga basin, Killip & Smith 28817 (F, NY, S, US); Williams 4823 (F, NY); Klug 3058 (B, F, NY, US); vicinity of Iquitos, Tessmann 5386 (B, type of I. trigona, NY); Rio Itaya, Tessmann 5158 (B, NY); Williams 3461 (F, US). BRAZIL: Amazonas: Rio Solimoes basin, Krukoff 8191 (NY); Rio Jurua basin, Ule 5460 (B, type, K); Krukoff 4560 (B, M, NY, 5, Utr), 4623 (B, M, NY, 5, Utr) ; Rio Madeira basin, Krukoff 1298 (B, K, M, Mich, NY, P, 5, US, Utr), 6449 (NY

    Brazil South America| Peru South America|