“A rolling stone gathers no moss.”  That was the creed of the Stone family, proclaimed like God’s own truth by Mr. Stone all through the two boys’ school years.  It was the inevitable punch line of the dinnertime tirade he thought of as a heartening pep talk for them — a kind of call to battle.  Mr. Stone had been in the Marines the year they cornered General Noriega in the Vatican embassy just before Christmas and bombarded him with nonstop rock-and-roll music, and now contracted road-paving equipment for land developers in California’s Central Valley.

His older son, Howard, a mousy — or, dare it be said, mossy — young man, with no particular ambition to roll anywhere, believed the family motto with every shrinking fiber of his uncooperative body.  He felt the truth of it almost crushing him sometimes, like one of the even more onerous stone tablets on which the other ten Commandments had been written.  In his heart of hearts, where he hid out a lot, Howard suspected he might never be good for anything but gathering moss.  His parents let him know (his father in no uncertain terms, his mother through her disappointed looks and pursed lips as she made him his bedtime Swiss Miss) that he was letting down his august family and its forwards course.

Howard’s brother Sebastian, on the other hand, with the name of the martyred saint and the nose of Mick Jagger, could indeed have been shot through with arrows and still look ecstatic, haughty, unperturbed.  He was a go-getter, Sebastian, on a moss-free roll toward the very top of whatever career he chose.  Moss virtually leapt out of his way when it saw Sebastian coming, his brown eyes alight from age three-and-a-half with the fires of ambition, his skateboard cutting like a scimitar through any difficulty with the other neighborhood children — who called Howard “Rock” to torment him and took away the liverwurst sandwich his mother gave him every morning in a brown bag, with two carrots, for his school lunch.  Sebastian sneaked out every day just before lunchtime to call in an order for the two-for-one Domino’s pizza special, and sold it for $5.00 a slice to the fifth graders at a shameless profit.

Sebastian was at Stanford Business School, and then Sun Microsystems.  Appropriate of course that he should be the sun, while Howard was the lowly moon — dreamy, feminine, and changeable.  Literally, too.  When Howard crept off apologetically to Foothill College to major in drama, he found himself playing Moon (in the person of Robin Starveling, a Tailor) in the spring performance of A Midsummer Night’s Dream, as the apex of his acting career.

The crisis came for Howard on his thirtieth birthday, when it had become apparent that his acting wasn’t going to pay his way, and his mother broke it to him after the chocolate-chip mint ice-cream cake — nicely, under the circumstances — that he couldn’t go on living at home.  He realized his whole worthless life had been leading to this.  He lay one last night on his childhood bed, and considered his position.  (Prone.)

The most shameful thing of all, perhaps, was that he happened to secretly like moss, and could see nothing wrong with gathering it.  How livid his father would have been to hear him admit that.  And further, Howard let himself think, plumbing the depths of his enormous treachery, he’d never quite bought into that “rolling stone” stuff — despite his father’s beligerently drumming it into them, despite the upward trajectory of Sebastian.  He would show them, he thought.  What did he have to lose?  He’d treat himself, for his birthday, the day of his bitter coming of age.  He’d let himself have one all-out, self-indulgent glut of mosses, the way other men might have a drunken orgy with a stock of rotgut whiskey.  He would make his degradation final and complete.  Go out with a bang, not a whimper.

So Howard holed up in a Motel 6, and on Sebastian’s cast-off iBook ordered himself a copy of the Moss Grower’s Bible, used, from Amazon.com, for $34.95 — almost the remainder of his life savings when he recklessly included the UPS 2^nd Day Air shipping.  (Sebastian had had more before sixth grade, after investing his money from the tooth fairy cannily in IBM stock).  It felt symbolic, a properly world-be-damned gesture.

But when the book arrived Howard soon forgot himself and his misery.  There were so many intriguing chapters, like Large Common Liverworts, and Bags, Jars, & Sandwich Boxes.  He was astonished to learn that there are roughly 10,000 species of mosses in the world, as well as hornworts and liverworts (of which he would become especially fond, perhaps because they subconsciously reminded him of his early diet of liverwurst).  He was enchanted by their names and by the stunning array of colors they came in, from the large brightly-colored purple tufts of Scapanias undulata, to the small coppery-red patches of Gymnomitrion crunulatum, to the deep reddish-brown tufts Marsupella emarginata forms, to the silvery-green, gray, or ochre tufts distinguishing G. obtusum and its cousin with the more pointed lobes, G. concinnatum.  Though Howard had been an indifferent student in school, he absorbed everything there was to know about mosses almost in one single ravished moment, like a religious conversion.

He had a moment’s youthful dalliance with the flamboyant Spanish mosses, picturing how they grew like wizard’s beards in eerie alligator-infested bayous in the deep South, Savannah and Okefenokee and New Orleans, where Howard’s favorite playwright Tennessee Williams had lived before drinking himself to death.  But he soon learned that above all he loved the mountain mosses, hardy and possessed of a more sparing character.  That they crept closely pressed against the rock spoke to his lonely heart.

He began making excursions into nearby oakwoods to examine live specimens in their native habitat — beside icy mountain streams, on wet boulders, on steep shadow-creviced rock faces.  He became fit.  He got up at the crack of dawn.  And in his mind as well, while sitting in a patch of sun thriving against his nature like Bryum dichotomum on an exposed south-facing veranda, Howard made long journeys to Europe and farther, to study how mosses grew there on slate walls, thatch, heathland, old cinders, and tombstones, which are encouragingly acidic.  (Not his father’s, of course — Mr. Stone had left word in his will that his highly polished marker in the National Cemetery in San Bruno, shaped like a somewhat smaller version of the Washington Memorial, was to be cleaned twice weekly rain or shine by the grounds crew.  There was a generous bequest for moss- and lichen-prevention compounds.)

Despite Mr. Stone’s last wishes, however, mosses changed Howard’s life.  They made a new man of him from the inside out.  They introduced ethical issues he could never have dreamed of — atrocities such as Victorian fern plunderers.  And dangers to be overcome — insects, frost, air pollution, acid tree bark.  But even in the face of these, the great-hearted generosity of moss experts was a revelation to him.  “I have never yet met anyone who despises a plant because it is small, unusual, or difficult to grow — quite the opposite.”  Now there was a creed!

Mosses contributed to societal good.  In World War II, Sphagnum mosses served as first-aid dressings on soldiers’ wounds.  In famines, peat mosses have been baked into bread.  In rural Britain, Fontinalis antipyretica was used to put out fires (absorbing as it does large quantities of water in the slow-moving rivers in which it grows).  The name, Howard learned, means “against fire.”  He was pleased to be acquiring ancient languages along with all the rest.

Though shy by nature, Howard was emboldened to join a Society, to meet and mingle with other moss lovers like himself.  That was where he met Betsy, a specialist in bulbils and gemmae, who he would marry in a mossy Mendocino grove when he was 42 and she 40.  They would have no children, but a houseful of the delightful chia pets Howard would, inspired, plant with fissidens bryoides.

Howard’s tremendous financial success was almost incidental, of no real interest to him, only the means of prolonging his happiness.  It happened despite his modest inclinations.  He’d begun simply at first, growing Bazzania tribolata in clay pots and Racomitriums on bits of broken roof slate (imitating the hard acid rock and clean mountain rain that gives them their nourishment in the wild, on barren screes and summits).  He built a small greenhouse from a kit purchased at Home Depot, and after his first big sale to the eager local nurseries, a larger one.  He experimented with growing alpine mosses by installing a Growlight in an old refrigerator his mother had discarded when she remarried.

His business thrived.  He sold mosses gathered from the wild to florists and home decorators, nurseries and horticulturists.  He sold mosses to landscaping firms for rich clients who wanted picturesque mosses on walls, eco-friendly mosses as ground cover in patios, gardens, and parks.  He soon had an acre of greenhouses in Half Moon Bay, with temperature control, reflective aluminum sheeting, fluorescent lights, two dozen employees, a fleet of trucks.  Something he’d learned early was to stand him in good stead at a key moment.  Sphagnum, decaying, is the major component of peat — which, in turn, is a major component of single malt Scotches.  He would make a very good deal with a distillery on the Isle of Islay, during the Scottish peat blight.

And when poor Sebastian, who had flown like Icarus so recklessly toward the sun, was punished for his overreach in the same way as the Greek, losing his job and Porsche and wife and Woodside house in the dot-com crash, Howard hired him to redesign his Web site and keep the propagation databases free from viruses.

Soon he let Sebastian take over the business entirely.  Howard had never really gotten over his uneasiness at profiting from what had been anathema to his father — a good man, he told himself, if misguided.  His conscience clear, Howard retired early with Betsy to a small damp cabin in the woods around Fort Bragg, where he grew to be very old indeed and could be found well into his upper nineties gazing dreamily at the north side of trees, or letting small green-coated pebbles roll down the slope of his leg from his stiff old knee into his pants cuff, with an expression of pure and uncomprehending joy.