1980 Miscellaneous Papers 19: 183-204 The Cryptocoryne albida group of mainland Asia (Araceae). Jacobsens milestone 1980 paper about the albida complex (albida, crispulata and retrospiralis). All other strap leaved forms (except APO) are placed as varieties of crispulata. 1991 Aqua-Planta 16(1): 1-33 Chapters Complete Original Die schmalblattrigen Cryptocorynen des asiatischen Festlandes. An update of the 1980 article with description of the varieties. Bigger, more pictures, broken down into sections because of its sheer size. 1992 Aqua-Planta 17(1): 18-25 En The rare and tricky species from peat bogs that prove difficult if not impossible to grow seem to respond very well when cultivated in humus-rich leaf-mould made from Beech leaves (Fagus sp.). 2002a Aqua-Planta 27: 150-151 En Der Cryptocoryne cordata Griffith - Komplex (Araceae) in Malesien More material gathered during recent years has shown that the hitherto held opinion of Cryptocoryne cordata Griffith, C. grabowskii Engler, C. zonata De Wit, and C. diderici De Wit as separate species is no longer tenable. They are therefore deprecated from full species and placed as varieties of C. cordata. (Jacobsen 2002).

2002b Aqua-Planta 27: 152-154 Original description of Cryptocoryne Xpurpurea Ridley nothovar. borneoensis En Cryptocoryne Xpurpurea Ridley nothovar. borneoensis N. Jacobsen, Bastmeijer & Y. Sasaki (Araceae), eine neue Art aus Sarawak Cryptocoryne Xpurpurea Ridley nothovar. borneoensis N. Jacobsen, Bastmeijer & Y. Sasaki is new variety found in South Kalimantan. The leaf blade is cordate, brown purple, flat to somewhat bullate. The spathe is 10-20 cm long, the limb 3-6 cm long, ovate and long acuminate, somewhat rugose, shiny bright red, sometimes dark red; the collar/collar zone is distinct, somewhat narrow, dotted towards the opening. 2008 Borneo Cryptocorynes Fourteen species of Cryptocoryne are recognized from Borneo: C. ciliata found throughout tropical Asia, C. longicauda also found in Johore; C. zonata, C. grabowskii, and C. edithiae show distinct affinities to the C. cordata group from the Malay peninsula; the remaining species, endemic to Borneo, do not show any special, close relationship with species from other areas. The synonomy, distribution, chromosome numbers, and ecology are treated. 2014a On Cryptocoryne cordata siamensis 2016 Hybrids and the Flora of Thailand revisited: Hybridization in the South-East Asian genus Cryptocoryne (Araceae) ABSTRACT The South-East Asian genus Cryptocoryne has been shown to hybridize more frequently than expected. Data are presented on the known naturally occurring hybrids including information on their discovery, naming, and recognition as hybrids. Many artificial hybrids produced over the years indicate that there are only relatively few barriers to crossing. A heterosis effect is prevalent in many encountered Cryptocoryne hybrids. Vegetative propagation is clearly an advantage in the establishment of hybrid populations and also in detecting the hybrids, since inferior hybrids have disappeared naturally. Our results on Cryptocoryne also suggest that when the South-East Asian floras become as well-known as temperate ones, the number of natural hybrids will be similar to those presently known from temperate regions.