By Lin Li

May 17 2019

As the many plants to be digitized in the Endless Forms project, members of the Cactaceae family are not only unique and charismatic, they are considered one of the most threatened plant groups in the world.

The body of a cactus is composed of succulent stem segments; the spines are modified leaves that are hardened and sharp, providing protection for the plants against herbivores. Yet, these prickly plants can burst out the most beautiful flowers you have ever seen. The flowers are showy and quite large with dozens of stamens and petals, ranging from creamy white to dark purple. Cacti are distributed throughout North and South America. The highest diversity occurs in the Sonoran and Chihuahuan deserts in North America, the Andean region, and the dry scrub forests of eastern Brazil. Known as a symbol of the desert, cacti have special morphological adaptations that allow them to flourish in dry and arid habitats; and they are an important component of the arid zone flora in the New World deserts.

Unfortunately, many species of Cactaceae are subject to high population vulnerability. A recent global Cactaceae assessment indicates that 31 % of all cacti are critically endangered.¹ In addition to slow growth rate, restricted distribution in small areas, and habitat fragmentation, illegal trading and poaching have become major causes for population decline of Cactaceae. The soaring popularity of cactus in the past decade have brought poachers to steal specimens from national parks and other protected areas. In 2014, more than 2,600 stolen cacti were seized at the US borders, up from 411 the year before.²

The herbarium at the New York Botanical Garden currently holds more than 11,000 cactus specimens that will soon be fully digitized. Herbarium specimens are a valuable source for conservation assessments. Data associated with the specimen such as locality and collection date can provide information on how changing environment conditions may influence the biology of the species. In addition, the number of verified specimens can be extremely useful as the “first pass” in sorting the species into categories used by the IUCN Red List—such as critically endangered, endangered, and vulnerable. Taxonomists who work in herbaria also play an important role in identifying the species threatened with extinction.