Determination of the nature of the cause of action alleged in Cbunt I of plaintiffs’ petition “is based upon construction of the complaint.” Williams v. Illinois Cent. R. Co., 360 Mo. 501, 229 S.W.2d 1, 2(3), 20 A.L.R.2d 322. “The form of the action is determined by the substance of the petition.” Webster v. Sterling Finance Co., 351 Mo. 754, 173 S.W.2d 928, 931. See also White v. Scarritt, 341 Mo. 1004, 111 S.W. 2d 18, 21(4) ; 1 C.J.S., Actions, § 46, p. 1100. And, although our courts have on several occasions “loosely stated the prayer is no part of the petition” — a thought “more accurately expressed by saying, the relief prayed for is no part of plaintiff’s cause of action” [Menke v. Rovin, 352 Mo. 826, 180 S.W.2d 24, 26(2, 3)] — ^“in determining the cause of action intended to be pleaded under the new code, we may consider the facts pleaded and relief sought.” [Kemp v. Woods, 363 Mo. 427, 251 S.W.2d 684, 688 (4)]. As has always been true [O’Donnell *424v. Baltimore & O. R. Co., 324 Mo. 1097, 26 S.W.2d 929, 935(17), and cases there cited; State ex rel. Brinkman v. McElhinney, Mo.Sup., 216 S.W. 521, 524(1)], if “the allegations of fact are ambiguous or susceptible of two constructions, the prayer may be looked to for the purpose of ascertaining the intention of the pleader.” [St. Louis 221 Club v. Melbourne Hotel Corp., Mo.App., 227 S.W.2d 764, 770(16), and cases there cit-ed],