The confetti that fell at midnight Monday in Annapolis marked more than the end of a hard-fought 90-day legislative session. For an unusually large number of issues, it signaled a new beginning.

Although Maryland lawmakers could claim some accomplishments, they left the capital with a long list of unfinished business, including debates over boosting funding for transportation projects and allowing table games at the state’s slots casinos.

Several measures — including two high-profile environmental initiatives of Gov. Martin O’Malley (D), bids to spur wind power and curb septic systems — were left to be studied this summer. And several other bills that fell short, including those to permit same-sex marriage and to legalize marijuana for medical purposes, will be brought back next year, supporters vow.

“There are a lot of things we want to do in this four-year term, and we’ve only begun accomplishing them,” House Majority Leader Kumar P. Barve (D-Montgomery) said.

Lawmakers will get a chance to do that sooner than usual.

They are scheduled to return this fall for a special session to redraw congressional district lines, and there is already talk of using the session to take on transportation funding and other issues.

Legislators cites several reasons for so much leftover business. The same-sex marriage debate monopolized their time and energy during a key stretch of the session, some of the governor’s proposals were particularly complicated, and there were an unusually large number of freshman lawmakers.

Annapolis also has a history of taking its time. Advocates of two issues that succeeded this year — direct shipment of wine from out-of-state vineyards and an alcohol tax increase — had spent years trying.

O’Malley had already started thinking about a special session agenda before the regular session ended. During a meeting last month with the two presiding officers of the legislature, he floated the idea of raising the gas tax to benefit transportation projects.

No commitments were made, and in an interview this week, O’Malley said he has not decided whether to seek new money for roads and mass transit during a special session, despite what he acknowledged are “tremendous transportation needs.”

Senate Majority Leader Robert J. Garagiola (D-Montgomery) said he thinks transportation should be “priority No. 1” in the fall. Lawmakers held off during the 90-day session on a bill sponsored by Garagiola that would have raised the gas tax by 10 cents and allowed for future increases based on inflation in transportation construction costs.

The state’s 23.5-cent-per-gallon tax on gas was last increased in 1992, when the average price per gallon nationwide was $1.14.

Garagiola’s bill, which also called for increasing vehicle registration fees, would have raised more than $500 million a year.

Not all lawmakers think the timing is right. Senate President Thomas V. Mike Miller Jr. (D-Calvert), who has championed gas tax increases in the past, said the legislature would have a hard time moving forward “as long as there’s still uncertainty in the Middle East and gas prices are as high as they are.”

Legislators could have an easier time selling a tax increase if they can tie the money to specific projects, such as a long-planned light-rail Purple Line between Bethesda and New Carrollton. And the timing of a fall session, most likely in September or October, might work to their advantage.

Maryland transportation officials expect federal transit officials to announce their decision this summer about whether the Purple Line can move forward into preliminary engineering, which would make the project eligible for federal funding.

Another initiative that was shelved early in the just-completed session would have allowed table games, such as black jack, at Maryland’s five authorized slots casinos and would have added a sixth gambling site, most likely at the now-shuttered Rosecroft Raceway in Prince George’s County.

That debate was delayed at the request of House leaders, who said more thought should be given to the future of gambling.

Prince George’s lawmakers have long resisted slots in their county, but advocates of the idea say some in the county’s delegation are coming around. Last year, the Senate passed a bill that would have allowed card games at the Fort Washington track.

Rosecroft was a beneficiary of a bill passed on the final day of this year’s session that provides operating subsidies to Maryland’s horse-racing tracks. Rosecroft’s new owners are hopeful it can re-open and thrive with the addition of casino-style gambling of some sort.

The morning after the 90-day session ended, O’Malley was looking ahead to next year. He vowed in a bill signing ceremony to press forward with his two environmental issues that failed to gain traction this year.

O’Malley encountered resistance from rural and business interests in his effort to restrict septic systems in large new housing developments. On Monday, the governor is scheduled to announce a work group to revisit the issue.

Del. Maggie L. McIntosh (D-Baltimore), who leads the House Environmental Matters Committee, said any viable proposal to limit new septic systems must be tied to the upgrade and expansion of public water and sewer systems in affected areas.

O’Malley’s goal of making Maryland one of the first states to develop offshore wind power ran into the reality of cost. Legislators embraced the concept but could not get over uncertainties about how much Maryland consumers would have to pay to subsidize wind energy.

Del. Dereck E. Davis (D-Prince George’s), chairman of the House Economic Matters Committee, said legislators would regroup this summer to try to get more definitive numbers from states, such as Delaware and Massachusetts, that are further along.

“Everyone just felt like if we could slow down and get more comfortable with the numbers, we could make a decision with better information,” he said.

Advocates for the outright legalization of medical marijuana scrapped plans early in the session in the face of opposition from Joshua M. Sharfstein, secretary of the Department of Health and Mental Hygiene.

He said the legislation would not have imposed sufficient limits on the number of dispensaries and types of conditions for which marijuana could be recommended by a doctor. At Sharfstein’s suggestion, lawmakers instead passed a bill calling for a group to rework the proposal and come up with a more controlled program that would be overseen by the state’s medical research institutions.

“I want to see a program move forward,” Sharfstein said.

Staff writers Aaron C. Davis and Katherine Shaver contributed to this report.