Orthomene schomburgkii (Miers) Barneby & Krukoff
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Authority
Barneby, Rupert C. & Krukoff, Boris A. 1971. Supplementary notes on American Menispermaceae. VIII. A generic survey of the American Tricilisisae and Anomospermeae. Mem. New York Bot. Gard. 22: 1-89.
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Family
Menispermaceae
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Scientific Name
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Description
Distribution and Ecology - VENEZUELA. Delta Amacuro: Carlos Blanco 566; Amazonas: Steyermark 102636. Surinam: Zuid River, Irwin et al. 57564. FRENCH GUIANA. Melinon 448 (1862) (P), 212 (1874) (P), 10 (1876) (P), Herb. Maire s n (P) "Western South America": Moros, 4000 ft, R. Pearce s n (Jan 1866) (BM). BRAZIL. Para: P. Cavalcante & M . Silva 1627 (IAN) (Rio Curua Una), Pires & N. Silva 11644 (IAN) & 11703 (IAN) (Belem, Ipean, Reserva Mocambo); Amazonas: basin of Rio Negro, along Rio Cauaburi, Maguire et al. 60117; Mato Grosso: Prance et al. 59251 (Serra do Roncador) (F); Territory Rondonia: Prance et al. 5970. COLOMBIA. Choco, near Juarin (alt 10/100 m), Duke 11495 (MO); Amazonas: Schultes & Cabrera 16389 (US). PERU. Huanuco, Aucayacu, Schunke 840 (F); San Martin: Schunke 1970/20. BOLIVIA. La Paz: Larecaja, near IMapiri, Krukoff 10923.This is the first record of the species from Mato Grosso and Territory Rondonia, Brazil, also from Choco, Colombia.
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Discussion
Anomospermum schomburgkii Miers, Ann. Mag. Nat. Hist. II. 7: 39, hyponym. 1851; Contr. Bot. 3: 71. 1871.
Anomospermum hostmanni Miers, Ann. Mag. Nat. Hist. II. 7: 39, hyponym. 1851; Contr. Bot. 3: 73. 1871.
.Anomospermum lucidum Miers, Ann. Mag. Xat. Hist. III. 14: 103, hyponym. 1864; Contr. Bot. 3: 72. 1871.
Anomospermum oblongatum Miers, Ann. Mag. Nat. Hist. III. 14: 103, nomen. 1864; Contr. Bot. 3: 71. 1871.
Anomospermum ovatum Miers, Ann. Mag. Nat. Hist. III. 14: 103, nomen. 1864; Contr. Bot. 3: 70. 1871.
Anomospermum schomburgkii var. lucidum Diels in Engler, Pflanzenreich 4(94): 186. 1910.
Prance notes on the label of Prance 59251: "wood with purple secondary phloem."
For range and ecology see [Mem. N. Y. Bot. Gard. 20(2): 26]. The following fruiting specimens have been reexamined in connection with this paper: Steyermark 87359; Prance, Pennington & Silva 1634; Prance et al. 5970; Prance, Silva & Pires 59251; Krukoff 10923; Buchtien 619; Froes & Pires 24107; Irwin et al. 57564; Mathias & Taylor 5108.
Sterile and staminate flowering material of O. schomburgkii is often strikingly suggestive of .Anomospermum reticulatum, the leaves being sometimes deceptively similar and the structure of the staminate flower itself offering no tangible differential characters. However, the thickened apex of the petiole in O. schomburgkii is conspicuously grooved lengthwise on the adaxial side, that of A. reticulatum terete; in absence of the fruit we find this to be the most constant and most easily observed difference between the two. Furthermore mature leaves from sunny exposure differ in intricacy of the reticulation, the mesh of O. schomburgkii being very close but coarse, with ultimate areoles ± 0.1-0.2 mm diameter and hardly more than twice as wide as the circumscribing veinlets, whereas that of A. reticulatum is finer and more open. Care must be taken to ignore young leaves of O. schomburgkii which display, when dried, a finer and more open mesh than the coriaceous older leaves, the state which was formerly known as var. lucidum (Miers) Diels. The costa of the leaves beneath, the axis of the inflorescence, and the outer surface of the sepals are all commonly glabrous in O. schomburgkii but exceptionally puberulent; those of A. reticulatum all obviously and often densely setulose (occasionally glabrous, see for example subsp. glabrescens from ZuHa, Venezuela described above). In both species the staminate inflorescences may be arranged in either of two ways, sometimes both appearing on the same plant: singly and paired at or just above the axils of expanded leaves; and scattered along slender leafless branchlets to form an apparently compound inflorescence many times longer than wide, even though the basic unit of 1-3-flowered branchlets is structurally a complete inflorescence in itself. However disposed, these individual inflorescences consist either of a single flower terminal to the axis but preceded by one or two lateral flowers opening centrifugally, or of the terminal flower alone, this preceded by one or two minute bractlets. In Orthomene schomburgkii the lateral flowers are only exceptionally present and when developed are usually elevated on a slender pedicel as long as themselves; in Anomospermum reticulatum they are normally present in all or most inflorescences and are either subsessile or very shortly pedicelled. Except for the character of the petiole all the contrasting characters are subject to enough variation to make them unreliable taken singly, however decisive when combined.
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Distribution
VENEZUELA. Delta Amacuro: Carlos Blanco 566; Amazonas: Steyermark 102636. Surinam: Zuid River, Irwin et al. 57564. FRENCH GUIANA. Melinon 448 (1862) (P), 212 (1874) (P), 10 (1876) (P), Herb. Maire s n (P) "Western South America": Moros, 4000 ft, R. Pearce s n (Jan 1866) (BM). BRAZIL. Para: P. Cavalcante & M . Silva 1627 (IAN) (Rio Curua Una), Pires & N. Silva 11644 (IAN) & 11703 (IAN) (Belem, Ipean, Reserva Mocambo); Amazonas: basin of Rio Negro, along Rio Cauaburi, Maguire et al. 60117; Mato Gr
Venezuela South America| French Guiana South America| Brazil South America|