Webs: Magic vs Mundane

The webs from the Web spell:

• Are flammable and damage creatures in them when set aflame (RAW). Arcana skill check to know this.
• Are thick enough to be easily noticed.

Webs from spiders:

• Are combustible (they burn away) but not especially flammable (they don’t produce flame when burned). A Nature check to know this.
• Are harder to spot and may require Perception to notice depending on circumstances (GM discretion).