在wp_mail变量中引用Wordpress标头函数

I am trying to reference the title of the site in a Wordpress mail form. I thought I could just echo but that doesn't appear to work. In other words, I want subject of the mail form to always be "RSVP from [site title here]".

// variables connect with rsvp form
$name = $_POST["rsvpName"];
$email = $_POST["rsvpEmail"]; 
$attend = $_POST["rsvpAttend"];
$number = $_POST["rsvpNumber"];
$website = '<?php echo bloginfo('name') ?>';

// variables defined for message to admin
$to = get_option('admin_email'); //sending to wordpress admin email
$subject = "RSVP from $website";
$headers = "From: $email";
$message = "$name $attend your invitation.
Number of guests in their party:  
$number";

Thanks for any help!

Your current code is creating a string with php tags in it. You need to use the get_bloginfo function:

$website = get_bloginfo('name');