Common Purslane (Portulaca oleracea L.) arrows point to seed pods and seeds
2015-07-20 Newark Oaks, DE
http://plants.usda.gov/core/profile?symbol=POOL
Description from Wikipedia:
https://en.wikipedia.org/wiki/Portulaca_oleracea
"It has smooth, reddish, mostly prostrate stems and alternate leaves clustered at stem joints and ends. The yellow flowers have five regular parts and are up to 6 millimetres (0.24 in) wide. Depending upon rainfall, the flowers appear at anytime during the year. The flowers open singly at the center of the leaf cluster for only a few hours on sunny mornings. Seeds are formed in a tiny pod, which opens when the seeds are mature. Purslane has a taproot with fibrous secondary roots and is able to tolerate poor, compacted soils and drought."
Pictures of seedpods and seeds also at Wikipedia link.