.beta.-D-xylopyranoside, (1S,10S,12aR)-2,3,6b,7,9,10,11,12,12a,12b,13,14,14a,14b-tetradecahydro-1-hydroxy-1,9,9,12a-tetramethyl-3-(2-methyl-1-propenyl)-4a,6a-methano-1H-phenanthro[1,2-c]pyrano[3,2-e][1,2]dioxin-10-yl O-.alpha.-L-arabinofuranosyl-(1--