Information:  - The Helvellaceae are a family of ascomycete fungi , the best known members of which are the elfin saddles of the genus Helvella . Originally erected by Elias Magnus Fries in 1823 as Elvellacei , it contained many genera . Several of these , such as Gyromitra and Discina , have been found to be more distantly related in a molecular study of ribosomal DNA by mycologist Kerry O'Donnell in 1997 , leaving a much smaller core clade now redefined as Helvellaceae . Instead , this narrowly defined group is most closely related to the true truffles of the Tuberaceae . According to the Dictionary of the Fungi ( 10th edition , 2008 ) , the family contains six genera and 63 species .  - A fungus (plural: fungi or funguses) is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms such as mushrooms and bracket fungi. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants and animals.  - Helvella is a genus of ascomycete fungus of the family Helvellaceae. The mushrooms, commonly known as elfin saddles, are identified by their irregularly shaped caps, fluted stems, and fuzzy undersurfaces. They are found in North America and in Europe. Well known species include the whitish "H. crispa" and the grey "H. lacunosa". They have been reported to cause gastrointestinal symptoms when eaten raw.  - The Archaea (or or ) constitute a domain and kingdom of single-celled microorganisms. These microbes (archaea; singular archaeon) are prokaryotes, meaning that they have no cell nucleus or any other membrane-bound organelles in their cells.  - Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA. Ribosomes are assemblies of proteins and rRNA molecules that translate mRNA molecules to produce proteins. As shown in the figure, rDNA of eukaryotes consists of a tandem repeat of a unit segment, an operon, composed of NTS, ETS, 18S, ITS1, 5.8S, ITS2, and 28S tracts. rDNA has another gene, coding for 5S rRNA, located in the genome in most eukaryotes. 5S rDNA is also present in tandem repeats as in "Drosophila". In the nucleus, the rDNA region of the chromosome is visualized as a nucleolus which forms expanded chromosomal loops with rDNA. These rDNA regions are also called nucleolus organizer regions, as they give rise to the nucleolus. In the human genome there are 5 chromosomes with nucleolus organizer regions: the acrocentric chromosomes 13,14,15,21 and 22. In Bacteria, Archaea and chloroplasts the rRNA is composed of different (smaller) units, the large (23S) ribosomal RNA, 16S ribosomal RNA and 5S rRNA. The 16S rRNA is widely used for phylogenetic studies.  - <section begin=lead />The human genome is the complete set of nucleic acid sequence for humans ("Homo sapiens"), encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. Human genomes include both protein-coding DNA genes and noncoding DNA. Haploid human genomes, which are contained in germ cells (the egg and sperm gamete cells created in the meiosis phase of sexual reproduction before fertilization creates a zygote) consist of three billion DNA base pairs, while diploid genomes (found in somatic cells) have twice the DNA content. While there are significant differences among the genomes of human individuals (on the order of 0.1%), these are considerably smaller than the differences between humans and their closest living relatives, the chimpanzees (approximately 4%) and bonobos.<section end=lead />  - The common name elfin saddle is given to a number of Ascomycete fungi in the order Pezizales. These medium to small fungi often have irregular saddle-shaped caps. Species include:  - The Tuberaceae are a family of mycorrhizal fungi. It includes the genus "Tuber", which includes the so-called "true" truffles. It was characterized by the Belgian botanist Barthélemy Charles Joseph du Mortier in 1822. A molecular study of ribosomal DNA by mycologist Kerry O'Donnell in 1997 found that a small clade now redefined as Helvellaceae is most closely related to the Tuberaceae.  - The nucleolus (or , plural nucleoli or ) is the largest structure in the nucleus of eukaryotic cells, where it is primarily responsible for the creation of ribosomes via a process known as ribosome biogenesis. Nucleoli also have other important functions like assembly of signal recognition particles and playing a role in the cell's response to stress. Nucleoli are made of proteins, DNA and RNA and form around specific chromosomal regions. Malfunction of nucleoli can be the cause of several human conditions which include diseases, disorders, syndromes and illnesses.  - Gyromitra is a genus of ascomycete mushrooms found in the northern hemisphere. The genus contains about 18 species.  - Bacteria (common noun bacteria, singular bacterium) constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals.    What entity does 'helvellaceae' has the relation 'parent taxon' with?
A:
pezizales