Part II: Cryptocoryne moehlmannii de Wit
The high mountains of the Leuser reserve in the east drain into to the Streets of Malaya. In that region of the Reserve grows Cryptocoryne minima Ridley described the in the part I of this article. The area where the plant is found, formerly known only from Penang and Kedah in Malaysia, is thereby much enlarged (Bastmeijer & Duyfjes 1996).
This article, part II, describes the western part of the Reserve, which drains into the Indo-Pacific where Cryptocoryne moehlmannii is found. Rather common in the lowlands, two new locations are also identified.
It is speculated that Cryptocoryne moehlmannii might be a synonym of Cryptocoryne pontederiifolia Schott, the latter one growing much more south of the Leuser Reserve.
Cryptocoryne moehlmannii De Wit
Cryptocoryne moehlmannii is described by H.C.D. de Wit based on material cultivated in 1977 by Friedrich Möhlmann in Einbeck, Germany (De Wit 1983, 1990). The plants originated from West-Sumatra and F. Möhlmann got them from a German agriculturist working there, Mr. Siegfried Jähn. Earlier, in 1955, plants of this species, which were not recognised to be new, were collected by W. Meijer in West-Central Sumatra near Sasok in a stream near the coast (Rataj 1975). These collections are stored in the Leiden Herbarium (Meijer 3504, 3505, 3507).
During the botanical inventory of the Leuser Reserve in July 1985, identical flowering material was collected in the lowland forest which drains to the west side of Sumatra. These plants are locally abundant, particularly in the swamp forests of the upper stream of the Lembang river (W.J. de Wilde & Duyfjes 20857) and in the swamp forests near Subulussalam along a tributary of the Alas river (W.J. de Wilde & Duyfjes 20434, 20460). Both locations are far more north in respect of the former collections.
In search of Cryptocoryne.
From the diary of July 1st 1985, we read the following on the habitats: “With a small company we travelled in two canoes for some days in the narrow, strongly meandering Krung (river) Lembang upstream in close lowland forest. We make slow progress because often barred by fallen trees and have to clear the way. Many trees are cut down illegally (in spite of it being a reserve) and some had fallen across the river. We looked for Cryptocorynes, but did not find any. On the sixth day we have however, we found some. The river had run nearly dry, and when you walked through it, it came up to about your ankles. Very low, not very dense trees with typical formed stems, probably Gluta sp. (Anacardiaceae), evidently tolerates wet feet, while they stand with their plank roots in the water. The stem feet are conspicuously surrounded by green pillows of leaves, like trees standing on a green island. After further investigation, 'the green islands' proves to be a pure colony of Cryptocoryne, to be determined later as Cryptocoryne moehlmannii. To our disappointment we do not see any inflorescence or fruiting here. From now it will be a matter of systematic search in the neighbourhood. We found some flowering specimens on the banks of the river, just above mean water level. These specimens grow at this moment totally emersed and are fertile! The soil is composed of soft, thick brown clay.”
The location more south, near Subulussalam, is periodical submerged swamp forest with rather open canopies. The species very abundant, growing in a more peaty soil. Flowering specimens at this site grow rather exposed, because of cutting and firing (in the dry period) for agriculture by the natives from the forests.
Fresh water tidal zone
The collection of Mr. Siegfried Jähn from 1977 is made in the fresh water tidal zone. Pictures of the habitat made by Mr. Jähn show clearly Nipa palms (Nipa fruticans Wurmb), which are bound to the tidal zone (Jacobsen 1990). The new locations mentioned here do not indicate any influence of tidal effects on the habitat of Cryptocoryne moehlmannii. The water level is just determined by the rainfall. As can be seen from the pictures, the level in the river may be rather low. This can extend for many days.
The plant has a creeping rhizome. The leaves have sheathed petioles up to 15 (20) cm and blades up to 10 (15) x 5 cm. The base of the blade is (truncate) cordate, the top is acuminate. The upper side of the blade is grass-green, the lower side pale green. The upper side seldom shows a greyish/purple tinge (Dötch 1983). The blade is rather thin, mostly even or at most with minor depressions. The edges can be slight undulate. Adult plants frequently shows cataphylls which reach up to 5 cm, even when not flowering.
The inflorescence has a lower part (the 'kettle') of about 1 cm, the upper part constricted and thick, and the lower part of the kettle thin with vertical grooves and a bit translucent, inside white, sometimes with a few purple spots. The valvule in the kettle is pale yellow. The tube is short, not exceeding 1cm, inside white, often with purple spots. The limb is 3 - 4 cm long, more or less opened, oblique to upright, depending of the degree of opening; inside deeply purple-brown to yellowish with purple spots, the inner surface slight uneven; a pronounced collar, mostly narrow around the throat but sometimes widened, dark purple-brown.
Female flowers 4 - 5 (seldom 6). The ovaries are beige with fine purple-red spots on it, which make it appear orange from some distance. Stigmas ovate, the centere slight depressed, white papillose. Olfactory bodies ca 4, rounded with sunken centere, yellow. Male flowers 20-30, yellow coloured.
Distinguishing Cryptocoryne moehlmannii and Cryptocoryne pontederiifolia
Sterile specimens of both species are very hard, if not impossible, to distinguish. The vegetative characters are almost the same. Cryptocoryne pontederiifolia easily get some greyish/purple tinge over the upper side of the leaves, even the lower side can be quite reddish when cultivated under 'good' conditions. Cryptocoryne pontederiifolia can grow a bit taller than Cryptocoryne moehlmannii. From both species there are variations in colour and shape of the limb, which bring both species very close together (Jacobsen 1988, Möhlmann 1988, van der Vlugt 1988). The limb of C. pontederiifolia has mostly a bright yellow colour (“sulphurea”), often with small red dots to a reddish trace. C. moehlmannii has mostly a purple limb of the spathe but this may be yellow coloured with purple red spots. C. pontederiifolia has a broad, wide open, mostly erect limb of the spathe with high collar. The limb of the spathe of C. moehlmannii may be also wide open and then erect. The collar of C. moehlmannii is variable, but not as high as in C. pontederiifolia. There is only a statistical difference in the lower part of the inflorescence between Cryptocoryne pontederiifolia and C. moehlmannii. Counts of the female flowers of about fifty inflorescences of both species shows an average of 4.9 for Cryptocoryne moehlmannii, while for Cryptocoryne pontederiifolia this average is 5.6, that means that the latter has more female flowers
But it must be remembered that there only exists a few live collections of both species. From Cryptocoryne pontederiifolia there is the 1975 type (described by de Wit as Cryptocoryne sulphurea de Wit) which originated from a plant nursery on Java, Indonesia (the original locality is not known but is probably from Sumatra), and the collection (Bogner 1739) by Bogner & Jacobsen made in 1985 near the typus locality at Tabakis (Jacobsen 1988). A new locality mentioned in Van Bruggen & Bastmeijer 1995 proved to be erroneous. From Cryptocoryne moehlmannii there is the original plant cultivated by Friedrich Möhlmann, collected by Siegfried Jähn in West Sumatra (Jacobsen 1988) and the two collections by the De Wilde & Duyfjes, mentioned in this article. More investigations on the variability are wanted. It is necessary that more living plants are available to come to a final conclusion if C. pontederiifolia and C. moehlmannii must be regarded as one species. Both plants have 2n=30 (Arends et al. 1982).
The cultivation of Cryptocoryne moehlmannii is quite simple. The plant grows easily in a normal fish tank. In emerged culture there are no special problems. In a normal soil mixture of sand, peat litter or fagus soil and some clay, you can grow splendid specimens, which will flower easily and make a lot of runners.
Summary (of both articles)
After rather comprehensive investigations in the Leuser area in the lowland forest, two Cryptocoryne species are found: Cryptocoryne minima Ridley, which is not rare in the lowland forest east of the Barissan mountains and Cryptocoryne moehlmannii de Wit (possibly a synonym of Cryptocoryne pontederiifolia Schott) which is a widespread species in the area that drains to the west coast of Sumatra.
Arends, J.C., Bastmeijer, J.D. & Jacobsen, N., 1982. Chromosome numbers and taxonomy in Cryptocoryne (Araceae). II., Nordic Journal of Botany 2: 453—463.
Cover (p. 41). Inflorescence of Cryptocoryne moehlmannii from Sasok with oblique limb of the spathe and longitudinal section of the kettle with a red tube.
Page 43. Map of distribution of Cryptocoryne moehlmannii and Cryptocoryne pontederiifolia.
Page 44. Top. The second author searching for inflorescences of Cryptocoryne moehlmannii in the Lembang river. Photo J.W.W.O. de Wilde. Bottom left. Cryptocoryne moehlmannii forms small islands around the trees in the Lembang River. Note to low water level. Bottom right. The camp at the Lembang River with view on the local massive occurrence of Cryptocoryne moehlmannii. Photo’s B.E.E. Duyfjes.
Page 46. Top. Locality of Cryptocoryne moehlmannii in the swamp forest near Subulussalam. The forest is partly cleared. Flowering plants grow in between the fallen trees. Photo J.W.W.O. de Wilde. Bottom. Spathe and fruit of Cryptocoryne moehlmannii from the Lembang River. Photo B.E.E. Duyfjes.
Page 47. Herbarium specimen of Cryptocoryne moehlmannii (Meijer 3505) in the Rijksherbarium Leiden. Photo J.D. Bastmeijer.
Page 49. Cryptocoryne moehlmannii from Sasok with yellow limb of the spathe. Photo J.D. Bastmeijer.
Page 50. Cryptocoryne moehlmannii in a aquarium (centere). Photo C. Kasselmann.