Question: What characteristic does the Quince and the Isoplexis share? 

full_context: Document 1: Pyrus cordata: Pyrus cordata, the Plymouth pear, is a rare wild species of pear belonging to the Rosaceae family. It gets its name from the city of Plymouth in Devon, where it was originally found in 1870 The Plymouth pear was one the British trees to be funded under English Natures Species Recovery Programme.
Document 2: Chaenomeles: Chaenomeles is a genus of three species of deciduous spiny shrubs, usually 1–3 m tall, in the family Rosaceae. They are native to Japan, Korea, China, Bhutan, and Burma. (Burmese: ချဉ်စော်ကား ) These plants are related to the quince ("Cydonia oblonga") and the Chinese quince ("Pseudocydonia sinensis"), differing in the serrated leaves that lack fuzz, and in the flowers, borne in clusters, having deciduous sepals and styles that are connate at the base.
Document 3: Digitalis: Digitalis ( or ) is a genus of about 20 species of herbaceous perennials, shrubs, and biennials commonly called foxgloves.
Document 4: Planchonia careya: Planchonia careya is a tree species in the family Lecythidaceae. Common names include cocky apple, cockatoo apple and billygoat plum. It produces an edible fruit which tastes like quince. Indigenous Australians use the bark and leaves in medications. The bark and roots were also used as a fish poison. It should not be confused with "Terminalia ferdinandiana", with which it shares some common names.
Document 5: Echium wildpretii subsp. trichosiphon: Echium wildpretii" subsp. "trichosiphon is an "Echium" that is found high up in the area of La Caldera de Taburiente on the Canary Island of La Palma. Like its sister plant on Tenerife, this plant forms a large rosette of silvery leaves which eventually give rise to tall spikes of bright pink flowers. The plant is biennial and dies after flowering. This plant can be grown in gardens, but requires good drainage and fairly mild conditions. The plant hates water falling in the centre of the rosette and will often rot in such conditions.
Document 6: Digitalis purpurea: Digitalis purpurea (foxglove, common foxglove, purple foxglove or lady's glove) is a species of flowering plant in the plantain family Scrophulariaceae, native to and widespread throughout most of temperate Europe. It is also naturalised in parts of North America and some other temperate regions. The plants are well known as the original source of the heart medicine digoxin (also called digitalis or digitalin).
Document 7: Quince: The quince ( ; "Cydonia oblonga") is the sole member of the genus Cydonia in the family Rosaceae (which also contains apples and pears, among other fruits). It is a small deciduous tree that bears a pome fruit, similar in appearance to a pear, and bright golden-yellow when mature. Throughout history the cooked fruit has been used as food, but the tree is also grown for its attractive pale pink blossoms and other ornamental qualities.
Document 8: Chilopsis: Chilopsis is a monotypic genus of flowering plants containing the single species Chilopsis linearis.
Document 9: Stapeliae: The genera of plants within the tribe Stapeliae are all to varying degrees stem succulents. Many of the species resemble cacti, though are not closely related, as an example of convergent evolution. The stems are often angular, mostly four-angled in cross-section, but in some species there are six or more, with some species of "Hoodia" having more than thirty angles. In size they vary from less than 2.5 cm/1" in length to over 2 m/6" tall. The leaves are in most species reduced to rudiments, sometimes hardened and thorn-like, arranged on bumps or tubercles on the angles. Some species, however, still have recognisable leaves, most notably the Indian species "Frerea indica", and some members of "Tridentea". Stapeliads are most abundant in warm, dry climates. In Africa, there are two separate regions where Stapeliads have most diversified: northeast Africa, and Southern Africa. Several species are endemic to the small island of Socotra off the Horn of Africa. The Arabian Peninsula, and most specifically the country of Yemen, contain another concentration of species. Several more are found in the drier parts of Pakistan, Afghanistan, India, Nepal, and Myanmar. A single species, "Caralluma europea" is found in Europe, in the very southern part of the Iberian peninsula. Stapeliads are often regarded as a climax group within the family because of their often structurally complex flowers. Certain aspects of these reproductive parts mirror the pollination systems in the Orchid family and represent a case of parallel evolution though both groups are quite unrelated and have developed similar, though not identical means to achieve the ultimate goal of pollination and therefore reproduction. Most stapeliads use flies as pollinators, that are attracted to odours resembling dung or rotting meat, emanating from the flowers. Many of the flowers also bear some physical resemblance to rotting animal carcasses, leading to their popular name of Carrion Flowers. However, not all stapeliads smell bad, or attract flies. Some species use beetles, bees, wasps, butterflies or moths as pollinators. Stapeliad flowers range in size from mere millimetres in species of "Echidnopsis" and "Pseudolithos" to those of "Stapelia gigantea" that can reach 40 cm/16" in diameter, and are some the largest of flowers to be found on any species of succulent.
Document 10: Pear: The pear is any of several tree and shrub species of genus Pyrus , in the family Rosaceae.
Document 11: Isoplexis: Isoplexis is a section of 4 species of flowering plants within the genus "Digitalis" in the plantain family Plantaginaceae. The species of section Isoplexis differ from other plants in the genus "Digitalis" in that their monosymmetric (sometimes called zygomorphic) flowers have a distinctive large upper lip rather than large lower lip and the species are endemic to the Canary Islands (the species "D. canariensis", "D. chalcantha", and "D. isabelliana") and Madeira ("D. sceptrum").
Document 12: Chaenomeles: Chaenomeles is a genus of three species of deciduous spiny shrubs, usually 1–3 m tall, in the family Rosaceae. They are native to Japan, Korea, China, Bhutan, and Burma. (Burmese: ချဉ်စော်ကား ) These plants are related to the quince ("Cydonia oblonga") and the Chinese quince ("Pseudocydonia sinensis"), differing in the serrated leaves that lack fuzz, and in the flowers, borne in clusters, having deciduous sepals and styles that are connate at the base.
Document 13: Echium gentianoides: Echium gentianoides is a synonym of "Echium thyrsiflorum" , a flowering plant in the borage family Boraginaceae with brilliant blue tubular flowers. It is endemic to the island of La Palma, the Canary Islands. It occurs in one location of La Caldera de Taburiente where it grows in sunny, rocky sites at altitudes higher than 1.800 m. The main threat described for this species is predation by goats.
Document 14: Digitalis laevigata: Digitalis laevigata, common name Grecian Foxglove or Giraffe Foxglove, is a species of flowering plant in the genus "Digitalis", in the family Plantaginaceae.
Document 15: Pseudocydonia: Pseudocydonia sinensis, the Chinese quince, is a deciduous or semi-evergreen tree in the family Rosaceae, native to eastern Asia in China, and the sole species in the genus Pseudocydonia. It is closely related to the east Asian genus "Chaenomeles", and is sometimes placed in "Chaenomeles" as "C. sinensis", but notable differences are the lack of thorns, and that the flowers are produced singly, not in clusters. The Chinese quince is also closely related to the European Quince genus "Cydonia"; notable differences include the serrated leaves, and lack of fuzz.
ground_truth: flowering plants