rootless duckweed

Names and Synonyms

Common Names

• rootless duckweed
• spotless water flaxseed
• spotless watermeal

Scientific Names

Accepted name

Synonyms

• Horkelia arrhiza
• Lenticula arrhiza
• Lemna arrhiza
• Bruniera vivipara

Regional and Traditional Names

Sources: Wikidata, Catalogue of Life

Taxonomical Classification

This plant belongs to the kingdom Plantae and is classified under the phylum Streptophyta within the class Equisetopsida. It is further categorized into the subclass Magnoliidae and the order Alismatales, falling under the family Araceae. Ultimately, the species is identified by the genus Wolffia.

Sources: The World Checklist of Vascular Plants (WCVP)

Distribution

This plant exhibits a specific geographical distribution primarily concentrated across various regions of Europe. In Northern Europe, its presence has been documented within Great Britain. Moving into Middle Europe, the species can be found inhabiting the landscapes of Austria and Belgium. Additionally, it extends its range through the territories of Czechia-Slovakia. Finally, the distribution continues through Germany, completing its documented European range.

Sources: The World Checklist of Vascular Plants (WCVP)

Botanical Identification

Ecology

The ecology of Wolffia arrhiza is characterized by its preference for stagnant or slow-moving freshwater environments, specifically inhabiting ditches and pools. This species exhibits a broad altitudinal distribution, occurring across a diverse range of elevations that begins at sea level (0 m AMSL) and extends up to a maximum elevation of 1600 m AMSL.

Elevational range max:

1600 m AMSL

Elevational range min:

0 m AMSL

Habitat :

ditches and pools

Life history

The life history of Wolffia arrhiza is characterized by its existence as a perennial organism, allowing it to persist through multiple growing seasons. As a specialized hydrophyte, it is fully adapted to aquatic environments, functioning as a cryptophyte where its biological structures are adapted to life within or upon the water surface. Furthermore, the plant exhibits a deciduous nature, shedding its structures in response to seasonal environmental changes.

Deciduousness :

deciduous

Life form :

hydrophyte

Life form :

cryptophyte

Lifecycle :

perennial

Morphology

The morphology of Wolffia arrhiza is characterized by its diminutive, non-woody structure, functioning as a self-supporting aquatic herb and forb. It exhibits an extremely minimal stature, with a mean plant height of 0 m and a maximum height reaching only 0.01 m. As an aquatic organism, it is categorized as terrestrial in its epiphytic classification and exists as an independent species, lacking any parasitic tendencies. Its growth form is strictly non-woody, maintaining a small, floating presence without the need for climbing or liana-like structures.

Aquatic :

aquatic

Climber :

self-supporting

Epiphyte :

terrestrial

Growth form :

herb

Growth form :

forb

Parasite :

independent

Plant height max:

0.01 m

Plant height mean:

0 m

Woodiness :

non-woody

Physiology

The physiology of Wolffia arrhiza is characterized by a C3 photosynthetic pathway and a non-carnivorous nutritional strategy. The plant possesses highly specialized, minute vegetative structures where the leaf form is distinctly ovate. These structures exhibit extreme miniaturization, with a mean leaf size of only 0.0019 cm² and a leaf width that ranges from a minimum of 0.05 cm to a maximum of 0.15 cm. Furthermore, the plant demonstrates a mean Specific Leaf Area (SLA) of 192.9 cm²/g, reflecting its unique morphological adaptations to its aquatic environment.

Carnivory :

non-carnivorous

Leaf form :

ovate

Leaf size mean:

0.0019 cm²

Leaf width max:

0.15 cm

Leaf width min:

0.05 cm

Photosynthetic pathway :

C3

Specific Leaf Area (SLA) mean:

192.9 cm²/g

Reproduction

The reproduction of Wolffia arrhiza is characterized by a complex interplay of sexual processes, as asexual reproduction is noted to be absent. The flowering cycle is highly flexible, with flowering periods that can occur across all months of the year, from January through December, and are considered variable. The plant produces extremely minute inflorescences, with lengths ranging from a minimum of $1 \times 10^{-4}$ m to a maximum of $2 \times 10^{-4}$ m. Pollination is driven by biotic mechanisms, specifically utilizing an insect pollination syndrome. Interestingly, self-fertilization is absent in this species. The resulting fruit is classified as an achene with a maximum width of 0.05 cm, and it is characterized by an indehiscent nature. The seeds produced are tiny, with a minimum length of 0.2 mm and a maximum of 0.5 mm, and a minimum width of 0.3 mm and a maximum of 0.4 mm. Finally, the dispersal of the species is primarily hydrochorous, relying on water to transport its seeds to new habitats.

Dehiscence :

indehiscent

Dispersal syndrome :

hydrochorous

Flowering time :

Dec

Fruit type :

achene

Fruit width max:

0.05 cm

Inflorescence length max:

2e-04 m

Inflorescence length min:

1e-04 m

Pollination syndrome :

insect

Pollination syndrome :

biotic

Reproduction asexual :

absent

Seed length max:

0.5 mm

Seed length min:

0.2 mm

Seed width max:

0.4 mm

Seed width min:

0.3 mm

Self fertilization :

absent

Sources: Global Inventory of Floras and Traits (GIFT)

Chemicals

Wolffia arrhiza has 2 reported phytochemicals identified across 0 scientific publications and several other databases. The most consistently reported chemicals include CATALASE, Peroxidase.

CATALASE

1. Izvestiia Akademii nauk. Seriia biologicheskaia

Peroxidase

1. Izvestiia Akademii nauk. Seriia biologicheskaia

Conditions

Wolffia arrhiza has 1 reported investigations on conditions identified across 0 scientific publications and several other databases. The most consistently reported conditions include salt stress.

Salt stress

1. Izvestiia Akademii nauk. Seriia biologicheskaia