Dictyna

Small spiders (1.5 mm to 4.5 mm in length). The most defining feature of these spiders is their "cribellum" (a specialized spinning plate) and "calamistrum" (a comb of hairs on the hind legs). They use the calamistrum to comb the silk from the cribellum, creating an adhesive, wool-like structure that catches dust and entangles insect prey very effectively.

Unless identified by a recognised expert, detailed photo(s) are required. 

They build small mesh-like webs on low plants and among dead plant stems.

Dictyna arundinacea and Dictyna uncinata are widespread in the UK.

Common.