This page also includes information now on the March 6th varieties.
The December 12th USPS Postal Bulletin indicates that this issue will be released January 27th, with a first-day city of Kansas City.
From my article from the October press preview:
There will be two different sets of coil stamps intended for volume mailers, issued in rolls of 3,000 and 10,000 stamps. One has four similar designs of stylized flags, the other features ferns.
There will be five designs for Ferns.
And, on December 20th, here they are: 
From the USPS on the 20th:
Five new stamps from the U.S. Postal Service celebrate the beauty — and popularity — of ferns.
A favorite with gardeners and florists, ferns range from tiny moss-like plants to giants as tall as trees. The ferns featured on the stamps are five of the approximately 380 different species found in North America.
Each of the five stamps depicts a close-up photograph of a different species of fern. The shapes and textures of the fronds stand out against a stark white background, highlighting the placement of the leaflets along each fern’s stem. The name of each fern — autumn fern, Goldie’s wood fern, soft shield fern, Fortune’s holly fern, or painted fern — is placed vertically in capital letters along one edge of the stamp.
Art director Phil Jordan chose the five images from among dozens of existing pictures by photographer Cindy Dyer. After Dyer isolated the fronds in her photos, providing a white background, Jordan tightened the focus on each to fit within the stamp borders. He rotated some of the fronds to provide visual interest and oriented them in relation to one another to form a unified whole.
These stamps add elegance to envelopes and are an exquisite continuation of the U.S. Postal Service’s tradition of offering stamps that feature beautiful plants.
The Ferns stamps are being issued in self-adhesive large coils of 3,000 and 10,000, which are designed to be used by businesses. This year the U.S. Postal Service will make large coil stamps available as Forever® stamps. Forever stamps are always equal in value to the current First-Class Mail® one-ounce rate.
Here’s the Digital Color Postmark for this issue:
How to Order the First-Day-of-Issue Postmark:
Customers have 60 days to obtain the first-day-of-issue postmark by mail. They may purchase new stamps at their local Post Office, at The Postal Store ® website at www.usps.com/shop, or by calling 800-STAMP-24. They should affix the stamps to envelopes of their choice, address the envelopes (to themselves or others), and place them in a larger envelope addressed to:
49-cent Ferns Stamp (3K & 10K)
Cancellation Services
8300 NE Underground Drive, Pillar 210
Kansas City, MO 64144-0001.
After applying the first- day-of-issue postmark, the Postal Service will return the envelopes through the mail. There is no charge for the postmark up to a quantity of 50. For more than 50, customers have to pay five cents each. All orders must be postmarked by April 1, 2014.
Technical Specifications:
Issue: Ferns Stamp
Item Number: 790000 (3,000), 790800 (10,000)
Denomination & Type of Issue: 49-cent First-Class Mail
Format: Coil of 3,000 or 10,000 (5 designs)
Series: N/A
Issue Date & City: January 27, 2014, Kansas City, MO (No Ceremony)
Art Director: Phil Jordan, Falls Church, VA
Designer: Phil Jordan, Falls Church, VA
Typographer: Phil Jordan, Falls Church, VA
Existing Photos: Cindy Dyer
Engraver: WRE
Modeler: CCL Label, Inc.
Manufacturing Process: Gravure
Printer: CCL Label, Inc.
Printed at: Clinton, SC
Press Type: Dia Nippon Kiko (DNK)
Stamps per Coil: 3,000, 10,000
Print Quantity: 45 million stamps (3,000), 50 million (10,000)
Paper Type: Nonphosphored, Type III; Phosphor Tagged Overall
Adhesive Type: Pressure-sensitive
Processed at: AVR, Clinton, SC
Colors: Yellow, Magenta, Green (7482), Black
Stamp Orientation: Vertical
Image Area (w x h): 0.84 x 0.73 in./21.34 x 18.54 mm
Stamp Size (w x h): 0.98 x 0.87 in./24.89 x 22.09 mm
Plate Size: 300 stamps per revolution
Plate Numbers: “C” followed by four (4) single digits
Coil Number Frequency: Plate numbers every 30th stamp below stamp image
March 6th varieties:
On March 6, 2014, in Kansas City, Missouri, the U.S. Postal Service will issue the Ferns (Forever priced at 49 cents) definitive stamp in five designs, in a pressure-sensitive adhesive (PSA) 10K coil of stamps (Item 777300). The stamp will go on sale nationwide March 6, 2014.
Issued earlier this year at the 49-cent First-Class Mail rate, these five stamps…
How to Order the First-Day-of-Issue Postmark:
Customers have 60 days to obtain the first-day-of-issue postmark by mail. They may purchase new stamps at their local Post Office, at The Postal Store website at www.usps.com/shop, or by calling 800-STAMP-24. They should affix the stamps to envelopes of their choice, address the envelopes (to themselves or others), and place them in a larger envelope addressed to:
Ferns Forever Stamp (10K)
Cancellation Services
8300 NE Underground Drive, Pillar 210
Kansas City, MO 64144-0001
After applying the first-day-of-issue postmark, the Postal Service™ will return the envelopes through the mail. There is no charge for the postmark up to a quantity of 50. For more than 50, customers have to pay five cents each. All orders must be postmarked by May 5, 2014.
There are two philatelic products for this stamp issue:
777316, First-Day Cover set of 5, $4.65.
777321, Digital Color Postmark set of 5, $8.20.
Technical Specifications:
Issue: Ferns Stamp
Item Number: 777300
Denomination & Type of Issue: First-Class Mail Forever Definitive
Format: Coil of 10,000 (5 designs)
Series: N/A
Issue Date & City: March 6, 2014, Kansas City, MO 64108 (No Ceremony)
Art Director: Phil Jordan
Designer: Phil Jordan
Typographer: Phil Jordan
Existing Photos: Cindy Dyer
Engraver: WRE
Modeler: CCL Label, Inc.
Manufacturing Process: Gravure
Printer: CCL Label, Inc.
Printed at: Clinton, SC
Press Type: Dia Nippon Kiko (DNK)
Stamps per Coil: 10,000
Print Quantity: 50 million stamps
Paper Type: Nonphosphored Type III
Adhesive Type: Pressure-sensitive
Processed at: AVR, Clinton, SC
Colors: Yellow, Magenta, Green (7482), Black
Stamp Orientation: Vertical
Image Area (w x h): 0.84 x 0.73 in./21.34 x 18.54 mm
Stamp Size (w x h): 0.98 x 0.87 in./24.89 x 22.09 mm
Plate Size: 300 stamps per revolution
Plate Numbers: “C” followed by four (4) single digits
Coil Number Frequency: Plate numbers every 30th stamp below stamp image