Which invasive plant is a perennial grass that grows from extensive rhizomes and has pointed glossy-white tips?

Torpedograss is indeed characterized as a perennial grass that spreads through extensive rhizomes, which are underground stems that allow the plant to expand its territory and recover after management attempts. The pointed glossy-white tips of its leaves are a distinctive feature that helps identify this invasive species.

In contrast, Paragrass is also a grass but differs in morphology and growth habits, often not exhibiting the same leaf tip characteristics. Soft rush is a sedge and does not have the same perennial grass characteristics, and Giant water fern is a floating aquatic plant that is unrelated to grasses. Thus, torpedograss stands out as the correct answer due to its specific traits of being a perennial grass with the described leaf features.