Aldrovanda is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of carnivorous plant

Carnivorous plant

Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...

s encompassing one extant species (Aldrovanda vesiculosa) and numerous extinct

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 taxa

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

. The genus is named in honor of the Italian naturalist Ulisse Aldrovandi

Ulisse Aldrovandi

Ulisse Aldrovandi was an Italian naturalist, the moving force behind Bologna's botanical garden, one of the first in Europe. Carolus Linnaeus and the comte de Buffon reckoned him the father of natural history studies...

, the founder of the Botanical Garden of Bologna, Orto Botanico dell'Università di Bologna

Orto Botanico dell'Università di Bologna

The Orto Botanico dell'Università di Bologna, also known as the Orto Botanico di Bologna, is a botanical garden operated by the University of Bologna. It is located at Via Irnerio, 42, 40126 Bologna, Italy, and open daily except Sundays....

.

The extinct species are known only from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 pollen

Pollen

Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

 and seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s, with the exception of A. inopinata which is also known from fossilised laminae

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

. Aldrovanda species are thought to be the evolutionary descendants of Palaeoaldrovanda splendens

Palaeoaldrovanda splendens

Palaeoaldrovanda splendens is an extinct species of carnivorous plant. It is thought to be the evolutionary ancestor of species in the genus Aldrovanda.P. splendens is only known from seed fragments found in the late Turonian-Santonian...

from the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

.

The organ of carnivory in Aldrovanda is the snap trap. Snap traps are only found in one other carnivorous plant genus, Dionaea, which includes the commonly known Venus flytrap. Aldrovanda and Dionaea have been shown to share a most recent common ancestor

Most recent common ancestor

In genetics, the most recent common ancestor of any set of organisms is the most recent individual from which all organisms in the group are directly descended...

 by analysis of combined nuclear

Nuclear DNA

Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...

 and chloroplast DNA sequences. When sequences of chloroplast DNA of Aldrovanda, Dionaea, and Drosera were analyzed alone, however, Aldrovanda and Drosera (sundews) were shown to share a most recent common ancestor. It has been proposed that this discrepancy between gene trees based on nuclear and cytoplasmic DNA analyses can be explained by chloroplast capture, as similar inconsistencies have been explained by this phenomenon.

Species

• †Aldrovanda borysthenica
• †Aldrovanda clavata
• †Aldrovanda dokturovskyi
• †Aldrovanda eleanorae
• †Aldrovanda europaea
• †Aldrovanda inopinata
• †Aldrovanda intermedia
• †Aldrovanda kuprianovae
• †Aldrovanda megalopolitana
• †Aldrovanda nana
• †Aldrovanda ovata
• †Aldrovanda praevesiculosa
• †Aldrovanda rugosa
• †Aldrovanda sibirica
• †Aldrovanda sobolevii
• †Aldrovanda unica
• Aldrovanda vesiculosa
• †Aldrovanda zussii

Several undescribed species are also known.

The distinctions between the various named species have been criticised, although SEM

Scanning electron microscope

A scanning electron microscope is a type of electron microscope that images a sample by scanning it with a high-energy beam of electrons in a raster scan pattern...

analysis of the seed structures seems to confirm the existence of different species.