diff --git a/jax/_src/scipy/sparse/linalg.py b/jax/_src/scipy/sparse/linalg.py
index 3fbcdfeed620..db87e8982d7d 100644
--- a/jax/_src/scipy/sparse/linalg.py
+++ b/jax/_src/scipy/sparse/linalg.py
@@ -288,10 +288,11 @@ def cg(A, b, x0=None, *, tol=1e-5, atol=0.0, maxiter=None, M=None,
   else:
     # real-valued positive-definite linear operators are symmetric.
     def real_valued(x):
-      return not issubclass(x.dtype.type, np.complexfloating)
+      return not issubclass(jnp.result_type(x).type, np.complexfloating)
     if callable(A) and x0 is not None:
       # we use output dtype as the proxy for dtype.
-      symmetric = all(map(real_valued, tree_leaves(jax.eval_shape(A, x0))))
+      symmetric = all(map(real_valued,
+                          tree_leaves(jax.eval_shape(A, x0))))
     else:
       try:
         # Prefer to use the dtype of the operator, if available.