#morphology

• Geological ablation — A conceptual form or terminological variant of 'ablație', used in classical geomorphology to describe the phenomenon of removal, washing away, or baring of rocks under the action of external agents (wind, flowing waters, waves). In soil dynamics, the term emphasizes the initial transport phase of fine detrital materials before they are deposited in sedimentary basins.
• Acalyculate — A morphological term used to describe a flower or floral structure that completely lacks a calyculus (an outer calyx or epicalyx). The calyculus is a collection of modified sepals or bracts forming an outer ring around the true calyx in certain plants (such as Malvaceae or Rosaceae families), and its absence serves as an essential taxonomic criterion for identifying and differentiating specific genera and species.
• Acanthiflorous — A plant morphological term used as an adjective to describe a plant whose flowers or inflorescences are equipped with spines, thorns, or sharp rigid bracts. This anatomical characteristic is frequently found in species of the Asteraceae family (such as thistles) or the Acanthaceae family, where the prickly elements surrounding the corolla serve as a protective barrier for reproductive organs against harmful insects and herbivores.
• Acanthiform — A descriptive term used in biological sciences to define an organic structure, organ, thorn, or anatomical outgrowth that exhibits a shape resembling a spine or an acanthus leaf. This morphological adjective is widely applied in taxonomy to describe the sharp apophyses of certain vertebrae, scale shapes in specific fish species, or the geometric configuration of cuticular spikes in invertebrates.
• Acanthocladous — A plant morphological term used as an adjective to describe a plant, shrub, or variety whose branches or shoots are equipped with numerous spines, thorns, or rigid sharp outgrowths. This structural configuration of the aerial axis represents a classic ecological adaptation mechanism (frequently found in xerophytes or plants from arid climates), aimed at reducing the evaporation surface and discouraging herbivory.
• Acanthocarpous — A plant morphological term used as an adjective to describe a plant, variety, or structure whose fruit is covered with spines, thorns, rigid spikes, or sharp outgrowths. This anatomical adaptation of the pericarp serves the primary purpose of protecting developing seeds against predators and facilitating zoochory, allowing the fruit to cling to animal fur for dispersal (as seen in the horse chestnut or certain Xanthium species).
• Acanthophilous — A plant morphological term used as an adjective to describe a plant displaying a strong ecological affinity for environments populated by spiny species, or whose leaves have partially or completely transformed into spines or thorns (a typical adaptation to drought). As a masculine noun, it defines a foliar anatomical structure evolutionarily modified into a sharp, rigid needle (as seen in cactus leaves or certain acacia species), serving to reduce water loss via transpiration and ensure self-defense.
• Acanthoid — A descriptive term used in biological and medical sciences as an adjective to define an organ, outgrowth, cellular structure, or anatomical element that has the appearance, shape, or characteristics of a spine or thorn. In human and comparative anatomy, it is occasionally used to describe the sharp profile of certain bony apophyses or the shape of membrane spicules found in specific pathological tissue modifications.
• Acariform — Having the form, appearance, or characteristic structure of a mite. In the hierarchical taxonomy of arthropods, the term defines organisms belonging to the superorder Acariformes, the largest and most diversified group of mites, notable for their distinct body segmentation (proterosoma and hysterosoma) and specific morphological traits of the mouthparts and legs.
• Acaroid — Resembling a mite in shape or appearance; ovoid, compact, and lacking visible body segmentation. In botany and chemistry, the term designates 'acaroid resin' (or acaroid gum), a natural yellow or reddish resinous substance extracted from Australian plants of the genus Xanthorrhoea, traditionally used in industry for manufacturing varnishes, spirits, printing inks, and in pyrotechnics due to its excellent burning properties.
• Acarpellous — Completely lacking carpels (modified leaves with a feminine reproductive role that constitute the gynoecium or pistil of a flower). The term specifically describes unisexual male (staminate) flowers or sterile flowers whose anatomical structure completely lacks a female reproductive apparatus, or where it aborted in early floral bud stages.
• Acrodolichomelia — A rare congenital structural malformation or anatomical feature characterized by disproportionate and excessive length of the distal segments of the limbs (hands and feet relative to arms and thighs, or unusually long digits).
• Acrodolichomelia — A spelling variant or medical transcription error for acrodolichomelia, describing a rare congenital structural malformation characterized by disproportionate and excessive length of the distal segments of the limbs.
• Acrodromous — Regarding leaves or venation patterns; exhibiting acrodromy, where two or more primary or secondary veins originate from the leaf base and run convergently toward the apex, joining at the tip.
• Acromegalic woman — The feminine form of the word 'acromegal'; it describes a female individual or an anatomical structure (conformation, physiognomy, symptomatology) affected by acromegaly or characterized by the traits of this disease. In women, the progression of the condition can cause, alongside skeletal changes, severe menstrual cycle disorders and macroglossia.
• Acropleurogenous — Developing, originating, or arranged both at the apex (apical) and on the sides (lateral) of a structure, plant stem, or hyphal filament. In mycology, the term describes a specific mode of spore or conidia formation and branching on conidiophores, where they are structurally generated across the entire terminal zone and the flanks of the main axis, ensuring efficient reproductive material dispersal.
• Acrosarcum — A type of simple, indehiscent fleshy fruit derived from an inferior ovary, characterized by the pericarp fusing tightly with an enlarged, fleshy receptacle that completely surrounds the seeds (as seen in gooseberries or certain cactus species). This complex plant anatomical structure ensures embryo protection and facilitates endozoochory, which is the dispersal of seeds through animals that consume the succulent outer envelope.
• Acrosincarpy — A structural condition or plant morphological anomaly characterized by the fusion, welding, or partial joining of individual carpels or fruits exclusively at their upper (apical) extremities, while the lower portions or bases remain distinct and separate during development.
• Acrospore — A type of asexual spore, conidium, or microscopic reproductive body that develops and separates exclusively at the upper extremity or apical zone of a specialized hyphal filament (conidiophore). This cellular structure, specific to lower fungi, is formed through terminal constriction or budding, ensuring highly efficient airborne dispersal of genetic material in the environment for species propagation.
• Acrostichoides — A taxonomic term utilized as a specific epithet in bilingual botanical nomenclature to describe a plant species (most frequently ferns, such as Polystichum acrostichoides) whose fronds, fertile structures, or sori arrangements strikingly resemble morphologically those of the genus 'Acrostichum'.