Information: - In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. In looser senses, the taller palms, the tree ferns, bananas and bamboos are also trees. Trees tend to be long-lived, some reaching several thousand years old. The tallest known tree, a coast redwood named Hyperion, stands high. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world. - Sigillaria is a genus of extinct , spore - bearing , arborescent ( tree - like ) plants . It was a lycopodiophyte , and is related to the lycopsids , or club - mosses , but even more closely to quillworts , as was its associate Lepidodendron . - A genus (genera) is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. - Lepidodendron also known as scale tree is an extinct genus of primitive, vascular, arborescent (tree-like) plant related to the lycopsids (club mosses). They were part of the coal forest flora. They sometimes reached heights of over , and the trunks were often over in diameter. They thrived during the Carboniferous Period (about 359.2 2.5 Mya (million years ago) to about 299.0 0.8 Mya) before going extinct. Sometimes erroneously called "giant club mosses", they were actually more closely related to today's quillworts than to modern club mosses. - Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Given the information above, choose from the list below the object entity that exhibits the relation 'taxon rank' with the subject 'sigillaria'. Choices: - family - genus - group - kingdom - species
A:
family