The Shulhan Aruch (Orah Haim 204:1) lists a number of foods over which one recites the Beracha of "She'hakol," including meat, fish, milk, truffles, mushrooms and eggs. (One recites "She'hakol" over eggs regardless of whether he eats them raw, scrambled or boiled.) Even though mushrooms and truffles grow from the ground, they nevertheless do not qualify as "vegetables" with respect to Berachot because they draw their nutrients from the air, and not from the ground.
If one mistakenly recited "Bore Peri Ha'adama" over meat, must he correct his mistake and recite "She'hakol," or has he fulfilled his obligation by reciting "Ha'adama"?
The Kaf Ha'haim (Rabbi Yaakov Sofer, 1870-1939), in Siman 204 (2), advances the argument that one who mistakenly recited "Bore Peri Ha'adama" over meat has nevertheless fulfilled his obligation, because meat can indeed be seen as something that grows from the ground. He infers such a theory from the Gemara's discussion in Masechet Eruvin (27b) concerning the laws of Ma'aser Sheni the tithe of produce that a farmer would either eat in Jerusalem or exchange for money that he would use to purchase food in Jerusalem. The Gemara imposes a number of restrictions on the kinds of food that may be purchased with Ma'aser Sheni money, including that the food must fall under the category of "Gidule Karka" foods that grow from the ground. Yet, when the Torah discusses this law, it explicitly allows using this money to purchase meat (Devarim 14:26). The reason given is that cattle graze in the fields and are thus considered "Gidule Karka." Accordingly, the Kaf Ha'haim reasons, meat has the status of foods that grow from the ground, and therefore even though ideally one recites "She'hakol" over meat, nevertheless, if one mistakenly recited "Ha'adama" he has fulfilled his obligation.
Later authorities, however, disagree with this ruling. Hacham Ovadia Yosef, in his work Hazon Ovadia (Laws of Berachot, p. 153), draws a basic distinction between the status of meat with respect to Ma'aser Sheni and its status regarding Berachot. Even if meat is afforded the status of "Gidule Karka" for purposes of Ma'aser Sheni, this does not render it a "Peri" a "fruit" according to the Halachic definition of the term. When it comes to Berachot, the determining factor is whether or not the given food can be said to be a "fruit." Meat is certainly not a fruit, even if the animal can be said to have grown from the ground, and therefore reciting "Bore Peri Ha'adama" cannot fulfill one's obligation to recite a Beracha over meat. One who does recite this Beracha over meat must recite "She'hakol" and only then may he partake of the meat. This is also the position of Rabbi Shmuel Wosner (contemporary), in his work Shevet Ha'levi (42:1).
Hacham Ovadia applies this ruling also in the case of one who mistakenly recites "Bore Peri Ha'adama" over mushrooms or truffles; in such a case, too, the individual has not fulfilled his obligation and must recite "She'hakol." In fact, Hacham Ovadia claims that even if one maintains that "Bore Peri Ha'adama" can fulfill one's obligation with respect to meat, he must concede that this Beracha cannot satisfy the requirement when it comes to mushrooms and truffles. The Rambam (Rabbi Moshe Maimonides, Spain-Egypt, 1135-1204) explicitly rules (Hilchot Ma'aser Sheni 7:4; listen to audio for precise citation) that Ma'aser Sheni money may not be used to purchase mushrooms or truffles, as they are not considered to grow from the ground. Hence, even according to the aforementioned rationale for accepting "Ha'adama" as a valid Beracha over meat, this Beracha would not fulfill the requirement with regard to mushrooms and truffles.
Summary: The proper Beracha over meat, eggs, mushrooms and truffles is "She'hakol"; one who recites "Ha'adama" over any of these foods has not fulfilled his obligation and must recite "She'hakol."
