Zomicarpella amazonica
Plant with 1-3 leaves and a dormant period of growth, otherwise evergreen. Rhizome creeping, 4-7 cm long and ca. .5 cm in diam., dark brown, with buds; roots 2.0-2.5 mm in diam. Petiole 10-15 cm long and 3-4 mm in diam., terete and slightly channeled (canaliculate) on upper side (towards leaf blade), dark green and sometimes reddish tinged; sheath short, 1.0-1.5 cm long. Leaf blade hastate-sagittate, 10-15 cm long and 6-9 cm wide, plain dark green or variegated with pale green blotches on upper surface and somewhat glossy, veins sunken, lighter green on lower surface and veins prominent; basal lobes obtuse, apex cuspidate; venation reticulate, midrib strong, 3-4 primary lateral veins on each side and mostly arising at the petiole insertion, the lower pair running into the basal lobes, veins of second order thinner, the primary lateral veins forming a submarginal collective vein 3-5 mm distance from the margin, a second thinner collective vein close (.5-1.0 mm) along the margin. 1-2 inflorescences in each floral sympodium, appearing with the leaves. Peduncle 5-14(-17) cm long and (1.8-) 2-3 mm in diam., green (whitish on lower part) and spotted with . small elongate red to reddish-brown blotches; enclosed at base by a few cataphylls, these up to (3-)4-5 cm long, whitish and red spotted. Spathe constricted, 4-6 cm long; tube convolute, 2.0-2.5 cm long; blade expanded, erect at first and then reflexed, 3.0-3.5 cm long, ca. 1.7 cm wide in the middle, apex acute; spathe outside whitish and spotted with small elongate red to red-brown blotches (as peduncle), inside cream-colored to whitish. Spadix shorter than spathe, 3.2-4.5 cm long; female zone adnate to spathe, .7-1.5 cm long and 3.0-3.5 mm in diam., male zone free, cylindric, 1.0-1.5 cm long and 1.8-2.0 mm in diam., cream-colored; male and female flowers contiguous; appendix slender, 1.2-1.6 cm long and ca. 1 mm in diam., smooth, whitish and spotted with very small red to red-brown blotches, apex blunt. Flowers unisexual, naked. Male flowers densely arranged, consisting of one stamen only (1-androus); stamens free, sessile to subsessile, ca. .5 mm long; connective inconspicuous; thecae opposite, subglobose, ca .. 3 mm in diam., opening by apical pore. Pollen extruding in strings, cream-colored, pollen grains inaperturate, globular, 18-20 µm in diam., exine spinose, spines 2.2-2.5 µm long. Gynoecium depressed bottle-shaped; ovary depressed-globular and somewhat compressed laterally, ca. 1 mm in diam., whitish to very pale green, unilocular with 3-6 (mostly 4) ovules on basal placenta; ovules anatropous, funicle quite short; style short, tapering towards stigma, .20-.25 mm in diam. below stigma, brownish to red-brown; stigma small (not broader than style), discoid, .20-.25 mm in diam., slightly papillose, brownish to red-brown. Infructescence with persistent lower part of spathe, this then dark red colored. Fruits a nearly globular berry, 5-7 mm in diam., whitish and somewhat reddish apically, with style and stigma remnant, 1-3-seeded. Seed irregularly ellipsoid, somewhat compressed laterally, 4-5 mm long and 2-3 mm wide, raphe conspicuous; testa thin, smooth, whitish; hilum somewhat sunken and deep purple around; usually connected with the swollen and enlarged funicle; embryo ellipsoid to pear-shaped, small, ca. .7 mm long; endosperm copious, white. Chromosome number: 2n = 26; size ranging from 2-7 µm, one pair of the chromosomes is smaller (ca. 2 µm) than the others (ca. 4.5-7.0 µm).
The genus Zomicarpella is more closely related to the genus Zomicarpa. Both have flat connectives of the male flowers, seeds with endosperm and a swollen funicle which is usually connected with the seed at maturity and breaks off at the placenta; Pilarum and Ulearum have seeds without endosperm. The pollen grains of the Zomicarpeae are similar: spherical, inaperturate and the exine is spinose, but there is a great difference in having sporopollenin in the genera Zomicarpa and Zomicarpella which is lacking in the genera Filarum and Ulearum (M. Hesse, pers. comm.). This is quite an unusual character because nearly all Aroideae have pollen without sporopollenin, only very few exceptions exist, e.g. Remusatia Schott; otherwise all other subfamilies of the Araceae have sporopollenin. Pollen without sporopollenin is not resistant to acetolysis. The chromosome numbers of the Zomicarpeae are: Zomicarpa Schott 2n = 20, Zomicalpella 2n = 26, Filarum Nicolson 2n = 28 and Ulearum Engl. 2n = 14.
BRAZIL, Edo. Amazonas, Rio Javari, near Atalaia do Norte, in rain forest in "terra firme", 10th October 1989, Bogner 1985 (holotype INPA; isotypes B, K, M, US); Benjamin Constant, sub mata; vernacular name "Tajazonho", 24th October 1945, Murca Pires & Black 986 (= IAN 17973) [herbarium specimen seen only as photograph]. The locality near Atalaia do Norte has been destroyed today by clearing of the rainforest. This species can be also expected from Peru, Department of Loreto, because the Rio Javari is the boundary between Brazil and Peru and it must be also present in the rainforest of the other, the Peruvian, riverside; unfortunately I could not visit this area during my visit.
Zomicarpella amazonica grows in the rainforest in "terra firme" in loamy soil, covered with leaf litter. It was found scattered on the forest floor in deep shade. The plants were flowering and fruiting during my visit in October 1989, but the male flowers were always eaten by insects. It is assumed that small beetles were visiting the inflorescences and eating the pollen, maybe these are also the pollinators. Plants with plain green and spotted leaf blades grow together in the natural population. Zomicarpella amazonica has a resting period with growth dormant, but does not lose its leaves. The growing and dormant periods have a yearly rhythm in cultivation. The plants are easy to grow in a stove house in Europe and we have had this species in cultivation for twenty years, where it also flowers regularly. illustrations