Primeng Button not showing label

I have primeng button in my angular4 application.

label of the button is not displaying.Button is displaying very small without label.

<div id="main">
  <form #newJobCleanUpForm="exForm" (ngSubmit)="onSubmit(exampleForm)">

    <label class="stylelabel" for="jobNumber"><span>Job Number</span>
      <input  type="text" pInputText  class="styletext" id="jobNumber" required  [(ngModel)]="jobNumber" name="jobNumber">
      <button pButton type="button"  label="Click"></button></label>
</form>
</div>