New York; Looking ahead to spring

Two seemingly diametrical trends go along by side through the spring and summer fashions shown recently on Seventh Avenue. On the one hand, we have blatant romanticism, signified by billowing puffed sleeves, cascades of lace, and riots of ruffles -- particularly in the ornate collection of Oscar de la Renta. The frills and furbelows there are as hearts-and-flowers, in their elegant way, as a sugary Harlequin novel, although plenty of other designers are on the ruffle kick, too.

Coupled with this unbridled femininity is a plethora of innovative trousers of all sorts. True, for the most part there is nothing overtly masculine about them. In many cases they are barely distinguishable from skirts -- some, in fact, so closely resemble skirts they are dubbed "pants skirts" by their creators.

The coexistene of such ostensibly opposite directions is among the anomalies of present-day fashion and is befuddling to the professional clothes-watcher whose job obliges her to make overview assessments. What can she say, when fashion is (a) easing back to old-fashioned fluff yet (b) also branching out in experimental directions -- all in the same season?

The stock answer is that diversity is the rule; and diversity (it is the operative word in current style) is meritorious. Diversity permits freedom of expression. Diversity is very democratic; it leaves no one out of the fashion swim. Every woman is allowed her own way of dressing: romanticism for some; skittish bloomers and/or practical culottes for others.

Should these choice lack appeal, diversity is expressed for the warm weather months to come in myriad other ways. Mary McFadden's Rosetta stone for the season is Egyptian lore, with such papyrus-inspired notes as hieroglyphics and palm fronds painted on her channel-quilted jackets and silk dresses. Her famous pleatings often take harem-pant form this season.

Options, options . . . more are offered in pure and simple separates in bright but softer colorings (in boat-neck pullovers over lightly gathered skirts or cropped trousers at Adri). There are jungle prints, but also delicate Liberty florals. Aztec and African motifs are frequent themes. Bill Haire adapts designs of beadwork and Masai warriors' shields for knits, embroideries, and hand paintings. High-visibility stripes of the blazer or yachting variety abound.

The stripes are punctuated with the perennial spring polka dots (squared as well as round for next year) and few are treated the same. Ralph Lauren does his clean cotton stripes in high colors with white in a serious of jackets, shorts, pants, bandeaux and summer-dance-at-the-country-club backless dresses. Perry ellis plays joker-is-wild with striped and puffy court-jester pantaloons, bustier tops, and cummerbunds edged in fluting. At Kasper, a daytime outfit consists of a striped crepe de Chine T-shirt with matching jamaica-length walking shorts.

Any analysis of the comings and goings of skirt lengths, waistlines, and the dimensions of shoulders and lapels needs qualification. If most designers use moderation in regard to padding and lapel widths, then Bill Blass squares shoulders and emphasizes lapels.

Hemlines are generally shorter. (Knees will be in evidence.) But it's wise to remember, before doing any alterations, that a mid-calf skirt is not demode. Collections like the splendid Geoffrey Beenes contain representations of all lengths for both skirts and pants, and any waistline goes -- including none at all. (The flowing chemise dress lives.)

Along with diversity, flexibility seems to be a fashion watchword of the moment. Ths minis at Halston -- silky jersey T-dresses for the beach and luxuriously beaded chiffon shifts (with matching cardigans or organza shirt jackets) for dinner parties -- are convertible. Wear the tasseled rope sash, clasped with an Elsa Peretti silver heart, at the natural waistline and the skirt just clears the knee.Sash the dress loosely and low at the hip, hitch the bodice up blouson-style, and voila, an ultrashort mini. Spring fashion is full of sleight-of-hand tricks.

The hybrid trouser-skirt, for instance, may have a fool-the-eye panel front, as Calvin Klein's crepe de Chine bermudas do. At Bill Blass, long fully-pleated evening pants, as wide at the ankle as the palazzo pajamas of the 1960s, move with the grace of a skirt. Many culottes, shirred at the waist as generously as dirndls, could be mistaken for skirts.

It exotica in trousers, which extends to roomy Indian dhotis cuffed below the knee, proves not to be every woman's sartorial dream, the more familiar tailored separates continue to exist in quantity. The prospects at Anne klein, for example: They are chiefly navy and cream raw silk tweeds for spring-summer '81.

And ruffledom is not always unrestrained. If ten layers down the skirt of a dance dress by Adele Simpson seem like too many to press, a few ripples at necklines and shoulders also make the point attractively. Fashion will find a way in these diversified times.