The defendants (Farm Advantage) in this patent infringement case argued that patent protection does not apply to plants. In their opinion plants were intended to be excluded from the patent system, as evidenced by the enactment of other statutes to provide protection to plants, specifically the Plant Protection Act (PPA) and the Plant Varieties Protection Act (PVPA). The defendants continued by referring to the Supreme Court's explanation of why plants were not previously deemed to be patentable: first, plants are "products of nature," and second, plants could not be described with sufficient precision to satisfy the written description requirement of the patent statute. The district court, however, sited Chakrabarty, and in its summary noted that mankind is learning how to modify plants in ways unknown to nature. In addition, advances in botanical understanding and analysis are improving precision of description. Nor is written description the only admissible form of accounting, since the deposit of new species in publicly available depositories has been authorized.