Downloading public key from OpenPGP card

[Andrew Lutomirski]

I have an OpenPGP card (an applet on a Yubikey NEO).

$ gpg --card-edit

gpg: detected reader `Yubico Yubikey NEO OTP+CCID 00 00'
Application ID ...: D2760001240102000000000000010000
Version ..........: 2.0
Manufacturer .....: test card
Serial number ....: 00000001
Name of cardholder: [not set]
Language prefs ...: en
Sex ..............: unspecified
URL of public key : [not set]
Login data .......: [not set]
Signature PIN ....: forced
Key attributes ...: 2048R 2048R 2048R
Max. PIN lengths .: 127 127 127
PIN retry counter : 3 3 3
Signature counter : 6
Signature key ....: 846D E20B 0ED9 0A19 5822  C7C6 3A95 152C 6C0E A581
      created ....: 2014-03-12 22:46:33
Encryption key....: 2BAC ADC6 725A 6D63 4BC7  9E2C 5A84 2069 31F7 0484
      created ....: 2014-03-12 22:46:33
Authentication key: C1F5 5179 D6AA E857 1C82  2AEF 20BB B0ED 8FE0 9C06
      created ....: 2014-03-12 22:46:33
General key info..: [none]

I want to read those public keys into my keyring.  How do I do this?

The OpenPGP specification says that this is GENERATE ASYMMETRIC KEY
PAIR, subcommand 0x81.  The scd function that corresponds to this is
iso7816_read_public_key

How do I get gpg to issue that command?  gpg2 2.0.22 doesn't seem any
more useful in this regard.