NOVELTY - An isolated polypeptide having beta -glucosidase activity is new.    USE - The polypeptide, composition, polynucleotide, and fermentation broth or culture mixture are useful for hydrolyzing a cellulosic biomass material selected from seeds, grains, tubers, plant waste or byproducts of food processing or industrial processing, stalks, corn cobs, stovers, leaves, grasses, perennial canes, wood, paper, pulp, and recycled paper, potatoes, soybean barley, rye, oats, wheat, beets, and sugar cane bagasse (all claimed).    ADVANTAGE - The enzyme and/or enzymatic compositions are capable of converting plant and/or other cellulosic or hemicellulosic materials into fermentable sugars with sufficient or improved efficacy, improved fermentable sugar yields, and/or improved capacity to act on a greater variety of cellulosic or hemicellulosic materials. The improved methods and compositions provide such enzymatic compositions, capable of yielding fermentable sugars at low cost and from renewable sources.    DETAILED DESCRIPTION - An isolated polypeptide comprises (i) an amino acid sequence that has at least 70% identity to SEQ ID NO: 135; or (ii) an N-terminal sequence and a C-terminal sequence, where the N-terminal sequence comprises a first amino acid sequence derived from a first beta -glucosidase, is at least 200 residues in length, and comprises one or more or all of SEQ ID NOs: 164-169, and where the C-terminal sequence comprises a second amino acid sequence derived from a second beta -glucosidase, is at least 50 residues in length, and comprises SEQ ID NO: 170, where the polypeptide has beta -glucosidase activity. INDEPENDENT CLAIMS are:    (1) a composition comprising the isolated polypeptide above;    (2) an isolated polynucleotide (i) comprising a nucleotide sequence having at least 70% sequence identity to SEQ ID NO: 83; or (ii) comprising a nucleotide sequence that is capable of hybridizing to SEQ ID NO: 83 or to its complement under high stringency conditions; or (iii) encoding an isolated polypeptide having beta -glucosidase activity, comprising an amino acid sequence that has at least 70% identity to SEQ ID NO: 135; or an isolated polypeptide having beta -glucosidase activity, comprising an N-terminal sequence and a C-terminal sequence, where the N-terminal sequence comprises a first amino acid sequence derived from a first beta -glucosidase, is at least 200 residues in length, and comprises one or more or all of SEQ ID NOs: 164-169, and where the C-terminal sequence comprises a second amino acid sequence derived from a second beta -glucosidase, is at least 50 residues in length, and comprises SEQ ID NO: 170;    (3) a vector comprising the polynucleotide of (2);    (4) a recombinant host cell engineered to express the polynucleotide of (2);    (5) a fermentation broth or culture mixture composition prepared by fermenting the recombinant host cell of (4);    (6) a method of hydrolyzing a cellulosic biomass material by contacting the biomass material with the polypeptide, composition, fermentation broth or culture mixture composition above; and    (7) a method of applying the polypeptide, composition, fermentation broth or culture mixture composition, or the method of hydrolysis, in a commercial setting or an industrial setting, where the method follows a merchant enzyme supply model strategy or an on-site biorefinery model strategy.