vs Compact Thread-leaf Century Plant

Cocconeis placentula compared with Agave microceps

Key Differences

• is Not Evaluated while Compact Thread-leaf Century Plant is Least Concern.

Taxonomic Classification

Rank		Compact Thread-leaf Century Plant
Kingdom	Chromista (Chromista)	Plantae (Plants)
Phylum	Ochrophyta (Ochrophyta)	Magnoliophyta (Flowering Plants)
Class	Bacillariophyceae (Bacillariophyceae)	Liliopsida (Monocots)
Order	Achnanthales (Achnanthales)	Asparagales (Asparagales)
Family	Cocconeidaceae	Asparagaceae
Genus	Cocconeis	Agave
Species	Cocconeis placentula	Agave microceps

Conservation Status

NE — Not Evaluated

Compact Thread-leaf Century Plant

LC — Least Concern

Physical Characteristics

Attribute		Compact Thread-leaf Century Plant
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

Native to Asia and Europe and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Norway, Portugal, Sweden, and Taiwan.

Compact Thread-leaf Century Plant

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Cocconeis placentula is among the most ubiquitous and widely studied freshwater and brackish-water diatoms worldwide, serving as a model organism for periphyton ecology and a key species in biological assessment of water quality. A member of the family Cocconeidaceae, this adnate epiphyte produces a characteristic ovoid frustule with fine transapical striae, a well-developed raphe system on one valve, and an elaborate pattern of areolae visible under electron microscopy. The species complex encompasses several morphological varieties (var. placentula, var. lineata, var. euglypta, var. acuta) that differ in fine structural details of the valve ornamentation. Cocconeis placentula colonizes the surfaces of aquatic plants, algae, rocks, and sediment particles in rivers, lakes, and ponds across a vast global range spanning Europe, the Americas, Asia, Africa, and beyond, tolerating a wide range of water temperatures, pH values, and moderate nutrient enrichment. Its abundance varies dramatically with substrate type, light availability, and water chemistry, making community composition data involving this species valuable in diatom-based paleolimnological reconstructions and modern bioassessment indices. As a benthic primary producer, C. placentula contributes substantially to the productivity of the photic benthos and serves as a dietary component for invertebrate grazers. Its remarkable cosmopolitan distribution and ecological flexibility make it one of the defining species of freshwater periphyton communities globally. Conservation status is not formally assessed.

Compact Thread-leaf Century Plant

<em>Agave microceps</em>, the compact thread-leaf century plant, is a perennial succulent in the family Asparagaceae native to Mexico, representing one of the smaller members of the ecologically and culturally significant agave genus. Agaves are iconic succulents of arid and semi-arid regions characterised by a rosette of thick, fibrous leaves typically edged with teeth and terminating in a sharp spine. <em>Agave microceps</em> typically forms compact, densely-leaved rosettes with notably narrow, thread-margined leaves, distinguishing it from larger agave species. It inhabits rocky slopes, dry grasslands, and scrublands in its native Mexican range, adapted to well-drained soils and periods of seasonal drought. Like all agaves, it is monocarpic, flowering once after many years of vegetative growth before dying, producing a tall flower spike that provides food resources for bats, hummingbirds, and insects. The species is classified as Least Concern by the IUCN, indicating a stable population without critical current threats, though many agave species face pressure from illegal collection for the horticultural trade and habitat conversion. Agaves play important roles in native ecosystems as food sources for specialist pollinators and as habitat elements on rocky hillsides. Biological traits including average lifespan in the wild, precise rosette dimensions, and population data remain poorly documented for this species compared to more commercially important agaves.