Disciphania ernstii Eichler
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Authority
Mori, S. A. 1987. The Lecythidaceae of a lowland Neotropical Forest: La Fumée mountain, French Guiana. Mem. New York Bot. Gard. 44: 1-190.
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Family
Menispermaceae
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Scientific Name
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Description
Species Description - Vines reaching a length of 12 m but often smaller, flowering when herbaceous but (in some forms) developing corky-laminated ropelike trunks up to 1 cm diam, the young branches and petioles smooth, channeled, glabrous, setulose, or pilosulous with fine decurved hairs, the leaf-blades likewise varying from glabrous to setulose or pilosulous beneath or on both sides, the pubescence sometimes confined to the veins beneath; petioles (3-)4-12(-15) cm long, ± twisted and thickened at base; leaf-blades of two types: a) associated with inflorescences of both sexes, herbaceous, concolorous, when dry olivaceous and opaque, all ovate- to suborbicular-cordate-acuminate, 6.5-20 cm long, 5.5-18 cm diam, the basal sinus 1.5-4 (-6) cm deep, either closed or open, the acumen triangular, subobtuse but mucronate; primary venation palmate, of 7 (-9) nerves divergent from base of blade, the two outermost on each side parallel and contiguous through ± 4-8 mm, the ascending lateral pairs conspicuously Y-forked near middle of blade, the costa with 1-2 pairs of secondaries arising beyond middle of blade, all these and the tertiary reticulation either prominulous both sides (commonly more sharply defined beneath) or rarely subimmersed, the ultimate defined areoles mostly >1 mm diam; b) associated with sterile branches, highly pleomorphic, varying from pentagonal to deeply 5-7-palmatilobate, the lobes obovate-acuminate, separated by obtuse, rounded sinuses, the blades often conspicuously whitish-maculate (suggesting Carica); inflorescences of both sexes shortly supra-axillary, solitary, (9-) 10-35-flowered, the flexuous peduncle ±2.5-6 cm long, the flowers at full anthesis subcontiguous (when pressed either contiguous or imbricated), the axis 3-9 (-10) cm long; bracts subulate, deflexed, pilosulous distally; flower at full anthesis rotately expanded into a shallow bowl, 11-18 mm diam, the sepals subcarnose, when fresh whitish, ochroleucous, greenish, or yellowish becoming brown and veiny when dry (5.5-) 6-9 mm long 1.8-6 mm wide, the 3 inner ones slightly broader, shorter, more concave and of thicker texture than the outer, all united at base through 1.5-2.5 mm, setulose dorsally toward the tip and ±papillose internally; petals 6, crowded into a 6-gonal, flattened disc 4-5 mm diam, adherent at base to the sepals, the free blades transversely rhombic to broadly obdeltate, thickened inwardly at the middle, grooved at base, ± 1.5 mm long, 1-2.5 mm wide across the top (the alternate ones narrower) all or at least the 3 larger tipped at the exterior-central angle with an incurved, subulate-triangular or papilliform appendage 0.1-0.6 mm long; stamens 3, glabrous, 1.2-1.5 mm long, almost or quite as wide, the filament and connective together rhombic in dorsoventral view, slightly incurved, produced beyond the anther-thecae as a small point, the thecae 0.7-0.9 mm long, introrse, separated widely at base but connivent distally; flower [female]: less widely opening than the [male] but the sepals not permanently connivent over the gynoecium, the sepals as in the [male] but slightly smaller, 5-6 mm long, 3-4 mm wide; petals adnate to the base of the opposed sepal, separate from each other, ± 1.8-2 mm long, the blades free in the distal half, carnose, truncate and 1-1.5 mm wide at apex, the appendage minute or 0; drupe oblong-ellipsoid, ± dorsoventrally compressed, 14-17 mm long, the leathery exocarp at first green, turning yellow and finally scarlet (but blackish when dried), the sweet mucilaginous mesocarp thin, deciduous, the endocarp ± 10-16 mm long, 9-11 mm wide, broadly 8-winged, the wings entire, undulate, or sometimes irregularly lacerate, the marginal ones 2.5-3 mm wide, in section ± 0.3 mm thick at base, the testa thin but rigid, 0.150.2 mm thick; seed-cavity in transverse section oblong-elliptic 3.5-4.5 mm wide, ± 2 mm high.
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Discussion
The group of species within sect. Sarcostephana characterized by cordate, ipomoea-like leaves subtending the inflorescence of both sexes combined with relatively large flowers brown or black when dried present a difficult taxonomic problem. Flowers and leaves of all the named entities are alike in structure and outline, and there are no known differences in the form of the drupe or endocarp. The criteria by which Diels (1910) distinguished the four species D. ernstii, D. appendiculata, D. glaziovii, and D. clausa are hardly fundamental, and some of them have since proved imperfectly diagnostic. Thus D. glaziovii was thought to differ from D. ernstii in having sepals of the pistillate flower connivent late in anthesis to form a sort of calyptra covering the gynoecium, but I cannot confirm this observation, and can see in D. glaziovii little more than a geographical race of D. ernstii characterized by relatively ample, suborbicular leaf-blades generally a little more densely pubescent than in the specific type from northern South America. It is certain that D. ernstii and D. appendiculata are aspects of one species. Diels thought that the petals of genuine D. ernstii lacked the subterminal appendage which is so well developed in the typus of D. appendiculata but this was a mistake. In the plant cultivated at Kew from seed sent to Hooker from Caracas by Ernst himself, that is in the progeny of the type of D. ernstii Eichl., the three larger petals of one staminate flower were found to bear appendages 0.4 mm long. In an isotype of D. appendiculata I found the appendage 0.5-0.6 mm long and in other collections which have been referred to this species the appendage varies from 0.3 to 0.6 mm in length. There are no perceptible differences in the leaves. On the other hand D. clausa, which has the inflorescence of typical D. ernstii, seems to differ in having leaves at once quite glabrous and of relatively thick texture combined with a disjunct range lying between those of D. ernstii proper and D. glaziovii. The differential character of a closed basal sinus to the leaf is not reliable, for I have seen individual leaves of typical D. ernstii from northern Colombia (cf Killip & Smith 14,655, GH) with a sinus varying from linear to closed by the overlapping descending lobes of the blade. With these disposed of as geographic varieties of D. ernstii there yet remain a few unplaced specimens belonging to the group, as well as D. tessmannii, described by Diels after completion of the monograph. The latter was said to differ from D. appendiculata in having glabrous leaves, but this would not of itself exclude the species from D. ernstii sens. lat. The striking peculiarity of D. tessmannii (of which the detached staminate flower and drupe hardly differ from D. ernstii) is the reduction of the inflorescences, both staminate and pistillate, to a short, often subcapitate spike of less than ten flowers. Combined with leaves at once glabrous and relatively small in context of its allies, the inflorescence marks D. tessmannii as reasonably distinct. Furthermore, D. tessmannii is sympatric in its small known range on the upper Amazon affluents in Loreto, Peru with a fourth form of D. ernstii which resembles var. glaziovii in the broad outline of the usually smaller leaves but is finely pilosulous almost throughout with uncinately incurved hairs. The only other close relative of the D. ernstii complex is the poorly known D. smithii which differs, so far as known to date, in its relatively elongate, bluntly hastate leaf-blade and a proportionately long and lax pistillate inflorescence of which the axis reaches a length of 4.5 dm and probably more. This like D. ernstii var. uncinulata is known only in the pistillate gender and the ultimate status of both remains to some degree contingent on discovery of the staminate flower. As defined here in the broad sense, D. ernstii is the only Disciphania characterized by pleomorphic leaves on the sterile shoots, leaves varying from cordate as in fertile branches through pentagonal to deeply palmatisect, when the spaces between the primary and secondary veins are often prettily mottled. Diels suspected that this type of pleomorphic foliage might prove to be a generic character of Disciphania, but this now seems unlikely. Palmatipartite leaves, variable in depth of lobing, are characteristic of sect. Meximenium, but are there associated with the inflorescence and found throughout the plant. The unique D. lobata of sect. Disciphania likewise has ample, variably lobed leaf-blades associated with the flowers, but the outline of the whole blade and of its forwardly directed lobes is of a type quite different from that found in D. ernstii and is not known to change in pattern between sterile and fertile branches.