The governor shall have power to grant respites or reprieves in all cases of convictions for offenses against the state, except treason or conviction on impeachment, but such respites or reprievies [reprieves] shall not extend beyond the next session of the board of pardons; and such board shall at such session continue or determine such respite or reprieve, or they may commute or pardon the offense, as herein provided. In cases of conviction for treason the governor shall have the power to suspend the execution of the sentence until the case shall be reported to the legislature at its next regular session, when the legislature shall either pardon or commute the sentence, direct its execution, or grant a further reprieve.