As part of a series of mapping startup purchases, Apple has acquired Embark, a popular public transit app that's used in cities across the US. Former Wall Street Journal reporter Jessica Lessin revealed the purchase today, saying that Apple had confirmed the buy but did not give further details. "Apple buys smaller technology companies from time to time, and we generally do not discuss our purpose or plans," said a spokesperson.

Last month, Apple purchased larger transit app HopStop, giving the same statement; it's also reportedly acquired crowdsourced mapping tool Locationary. Since dropping Google Maps last year and shifting to its own mapping system, Apple has been playing catch-up, and public transit was one of the glaring gaps in its original service. With these purchases, Apple is clearly shoring up this part of Maps, but it's not yet clear how Embark or HopStop will eventually be integrated.