Anatomy, physiology and development

Cactus anatomy and shoot organization

The succulent shoot combines water storage, photosynthesis, transport and plant support. Its structure becomes understandable when internal tissues are related to areoles, ribs and growing regions.

In many cacti, atmospheric carbon dioxide uptake occurs mainly at night. Light is still needed during the day. CAM links these two periods through temporary carbon storage in organic acids.

Root structure and water uptake

The root system combines plant anchorage, mineral uptake and water exchange with the substrate. Its function changes during drought, after rehydration and as tissues age. Root shape is only part of this system.

Structure and development of cactus flowers

A cactus flower is a complex reproductive structure in which floral organs combine with tissues bearing shoot-like features. Observing successive developmental stages helps explain the origin of the inferior ovary, pericarpel and differences between species.

Structure, development and functions of spines and glochids

Spines and glochids arise in areoles, but their structure and functions vary. Microscopy reveals both the attachment mechanism and specialized structures involved in water movement or nectar secretion. These processes need to be considered separately.

Modern cacti are terminal branches of a shared history, not a series of forms leading from leafy to globose plants. Phylogenomics distinguishes relatedness, structural similarity and the rate at which species arise.

Scientific names, synonyms and taxon boundaries

A botanical name links a plant to a description, a nomenclatural type and a particular taxon concept. Synonyms and provenance data connect a modern card with an older label and literature.

Crossing, selection and clonal propagation use different properties of inheritance. Interpreting cactus offspring requires distinguishing genotype from appearance, a single-gene model from a complex trait, and pollination outcome from confirmed seedling parentage.

Cactus frost-hardiness physiology

Extracellular freezing, dehydration, sugars, mucilage and hormonal signalling explain some differences between cacti. Plant provenance, organ and season also change tolerance.

Cristata and monstrous forms, growth organization and possible causes

A crested or irregular shoot describes a developmental outcome. Establishing its cause requires separate evidence, including meristem observation, clone comparisons and sometimes genetic or phytopathological testing. [Mauseth 2025]

Cactus tubercles. Shape, arrangement and examples

Eight diagrams help compare traits, but combine different criteria. Each example must be related to the species description and distinguished from the illustration's simplification. [Britton and Rose 1923]

Blossfeldia liliputana and survival of severe dehydration

The stem of Blossfeldia liliputana can shrink to a thin disc during drought. Anatomical studies and a prolonged drying experiment explain how such a small plant retains the ability to rehydrate. [Barthlott and Porembski 1996]