IM not good at this because I'm just learning too, but I'm going to take a guess at goosegrass maybe. I was thinking dallisgrass possibly, but I need to see the seedhead to have any confidence that I'm right. I'm going with goosegrass as my guess. Here is a link that might help for comparison: http://newsomseed.com/Weeds.html By posting a response, I subscribed anyways...so look forward to hearing from the experts, because I am NOT one. Just putting my guess out there primarily.
It is kind of early in the year for Goosegrass. I might not know exactly what it is, but the type of grass that it needs to be selectively controlled in will help me give better advice. I am guessing the lawn is Zoysia japonica of some kind growing in the shade. It is not thick like Zoysia growing in the sun. Reason why I need to know what kind of lawn it is growing in, is I know how to kill most grassy weeds. However, the treatment is very different in a warm season grass vs a cool season grass. It can be very different depending on what type of warm season grass I need to preserve.
took teds input and went looking at pics of orchardgrass and found this one: http://caes2.caes.uga.edu/commodities/turfgrass/georgiaturf/weedmngt/grsweedpages/dacgl.html Thought it might help.