R. Simeon draws a distinction between one kind of property and another: property that is known to the husband [the wife] may not sell, and if she has sold it or given it away her act is void; [property, however,] which is unknown to the husband she may not sell, but if she has sold it or given it away her act is legally valid.

 כתובות 8.2
רבי שמעון חולק בין נכסים לנכסים׃ נכסים הידועים לבעל, לא תמכור; שאם מכרה ונתנה, בטיל׃ ושאינן ידועים לבעל, לא תמכור; שאם מכרה ונתנה, קיים

[If a married woman] came into the possession of money, land should be bought therewith and the husband is entitled to the usufruct. [If she came into the possession of] produce that was detached from the ground, land should be bought therewith and the husband is entitled to the usufruct. [If it was] produce attached to the ground, the land, R. Meir ruled, is to be valued as to how much it is worth with the produce and how much without the produce, and with the difference land should be bought and the husband is entitled to its usufruct. The Sages, however, ruled: all produce attached to the ground belongs to the husband and only that which is detached from it be longs to the wife; [with the proceeds of the latter] land is to be bought and the husband is entitled to the usufruct.

  כתובות 8.3
נפלו לה כספים-- יילקח בהן קרקע, והוא אוכל פירות׃ פירות תלושין מן הקרקע-- יילקח בהן קרקע, והוא אוכל פירות׃ פירות מחוברין לקרקע-- אמר רבי מאיר, שמין אותן כמה הן יפים בפירות, וכמה הן יפים בלא פירות; והמותר-- יילקח בהן קרקע, והוא אוכל פירות׃ וחכמים אומרין, פירות מחוברין לקרקע, שלו; ותלושין מן הקרקע-- שלה, ויילקח בהן קרקע, והוא אוכל פירות