Utricularia humboldtii – the Bladderwort in a Bad Place

Reprinted from the Journal Trifid No. 3/2005:

Utricularia humboldtii × quelchii
Utricularia quelchii × praetermissa

The large genus Utricularia is found through all the world and is divided in sections according the Taylor´s monography. Especially beautiful orchid-like species grow in the Latin America and these are referred to the sections Orchidioides and Iperua. A similar species to them is U. longifolia yet, but it seems a separated one by evolution.

I was succesful in hybridization of some of the large-flowered bladderworts and I got flowering but infertile hybrids.If we admit that the ability of species to hybridize means their close affinity, then this reasults brought remarkable facts for taxonomy.

If we examine photos of various members of the Orchidioides section, we see great differences among endemits of Guyana Highlands (U. campbelliana and U. quelchii) and other species (U. alpina, U. endresii, U. jamesoniana, U. praetermissa etc.). I tried to hybridize just the very different species. The hybrids between U. alpina (♀) × U. campbelliana or U. quelchii (♀) × U. praetermissa prove that the Orchidioides section is probably a natural unit.

But, of course, a great surprise was a succesful hybridization between U. humboldtii (♀) × U. quelchii. The result was a beginning of not the same morphologically but at the same time apparently intermediary progeny. The plants are vital, they proliferate well vegetatively, they form stolons as with U. humboldtii, but they are smaller and have bare flowered low stalks after U. quelchii. Unlike this the fertilization of U. humboldtii with U. geminiloba pollen was not succesful despite the fact that these two species are referred to the same Iperua section. I had some doubts if these sections were so close and thought they might be connected in one taxon. Areals of these sections are absolutely isolated for a very long time. This isolation of grandbladdeworts had to become in the time of tectonic breaks, sometimes in the end of Mesozoic, when the Brasilian peak broke. It was formed from the created a channel by which the Amazon river is running. Between two fragments of the precambric peak the Amazon basin is found holding tertiary sediments and also hosting other vegetation, i.e. the Amazon rain forest. The observed bladderworts don´t grow there. Also the Ands, where some species of the Orchidioides section penetrated to, are far younger geohistorically than the Brasilian peak.

Utricularia alpina × campbelliana

We are getting an ideal picture, a generalized map with drawed areals of the Orchidioides section to the North and the West of the Latin America and of the Iperua one in isolation to the Southeast of Brasil. But this ideal is in a sharp contrast with the arela of U. humboldtii species to the North, in Guayana Highlands. This species belonging to the Iperua section because of similarities with U. nelumbifolia is in fact in a bad place. Of course, it has arched stolons as with U. nelumbifolia as well as special seed with a green very developed emrbyo (both explained as adaptation to symbiosis with bromeliads). However we must say duelly that leaves of U. humboldtii are very different by sharp, colour and firmness from leaves of U. nelumbifolia, while they are very similar in all the three characters just to U. quelchii. The mutual areal of the two endemits of Guayana Highlands, their morphology and the ability to hybridize each other support the possibility to re-refer U. humboldtii to the Orchidioides section.

Of course, a taxonomical consequence would be a loss of the nomenclature type determined by Taylor for the Iperua section. It would end and the left group of species would form a section with a some new name. Perhaps the ideal tool for an explanation of relationships here will be the cytotaxonomical methods. Let´s wait, perhaps someday specialists in thourough biochemical and mathematical methods will be succesful in getting other arguments.


RNDr. Miloslav Studnička - The director of The Botanical Garden in Liberec, Czech republic.