User:WikiGryphon/Warnstorfia exannulata

 Warnstorfia exannulata  is a leafy branching wetland moss in the genus Warnstorfia within the family Amblystegiaceae and class Bryopsida. This bryopsid moss is also known as Ringless-Hook Moss or Warnstorfia moss. It is the most common species of the genus in wetland environments and has a high phenotypic plasticity making it slightly cryptic and difficult to distinguish. It can grown in acidic soils like fens and bogs, or in freshwater pools and lakes.

Species Description
Warnstorfia exannulata is often a interwoven mat of glossy moss, yellow-green when young and matures to be dark-green, purple-brown, to reddish-brown. W. exannulata can have either regular or irregular pinnate branching and can have secondary pinnate branching. Stems are often curved. Main stems can grow up to 30cm in length depending on growing conditions, with one study finding their longest sample at 28cm aged approximately 8 years old. The stem and branch leaves are similar in shape with the branch leaves being slightly thinner on average. Leaves are linear-lanceolate in shaped about 3-4mm in length gently tapering, and can be varying between straight to falcate. Base of stem leaves is very slightly decurrent, which can be a identifying trait of this species in comparison to other Warnstorfia species. Strong single costa that extends up two thirds of the leaf. Alar region is strong and makes two triangular regions of 1-3 rows of cells at the base of the leaf. Alar region is made up thin walled rectangular shaped cells that are distinctive from elongate lamina cells of the rest of the leaf. Cross section of stem indicates characteristic double layer of cortical cells that have thick walls whereas central medullary cells are more thinly walled.

Reproduction
Sporophyte structures are rarely found suggesting that this moss more readily reproduces asexually through fragmentation. Sporophytes have red-brown seta and brown sporangia lacking an annulus at mouth of sporangium. Sporophytes are curved and seta has double twist at base of sporangium. Species is dioicous.

Variation
W. exannulata can have a high amount of phenotypic plasticity depending on what kind of habitat it is growing in. Plants that grow submerged in water tend to grow longer and have longer leaves than their terrestrial counterparts. This is likely due to increased competition to of light and CO2 resources with phytoplankton in the water column, whereas terrestrial plants are shorter to avoid herbivory and access to light.

W. exannulata may be temperature dependent in growth during the summer months in polar regions. Guo et. al found a correlation between summer growth leaf and branch density on specimens in Finland with the ambiant temperature during the summer months. There was a higher density of branching and leaves during warmer ambient temperatures of this season.

Range
W. exannulata bipolar and mainly found in the Northern Hemisphere. It is readily found from high arctic latitudes and down into temperate regions across Canada, the Northern United States of America, Northern Europe through to the Iberian Peninsula, and Northern Aisa. It has also been found in intermediate populations in more southern latitudes in alpine environments in South America, Asia, Southern Australia, and Southern New Zealand.

The polar range of this moss has made it the study of research looking at increasing UV-B effects due to climate change. There was no sigificant change to W. exannulata after a 3 year exposure experiment to UV-B while it was in a fen environment.

Bogs, Fens, Swamps, Peatlands
W. exannulata grows in mineral rich fen, swamps, bogs, and peatland environments where soils are slightly acidic. It has been found to live in fens, lakes, and seepage pools where there is an anthropogenic effect. It frequently grows in a matted pattern which can result in carpeted areas throughout wetlands of a single species, but is also common in multi-species carpets that can

Pools and Lakes
W. exannulata frequently found in freshwater pools that are driven by rain, snowmelt or glacier-melt in arctic and alpine regions. Can grow submerged in pools and attach to muddy pool bottoms which frequently results in longer stemmed individuals. Also grows abundantly along edges of pools and lakes among other bryophyte species like Sphagnum moss. Pools have low water turnover and few inputs other than melting water and precipitation, leading to higher eutrophication and establishing a slightly acidic environment.