<link href="//netdna.bootstrapcdn.com/bootstrap/3.1.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<form class="form-inline">
<fieldset>
<legend>Form Name</legend>
<div class="form-group">
<label class="col-md-4 control-label" for="data_ini"></label>
<div class="col-md-1">
<input id="data_ini" name="data_ini" type="text" placeholder="Início" class="form-control input-md">
</div>
</div>
<div class="form-group">
<label class="col-md-4 control-label" for="data_fim"></label>
<div class="col-md-1">
<input id="data_fim" name="data_fim" type="text" placeholder="Fim" class="form-control input-md">
</div>
</div>
</fieldset>
</form>
