5 SULPHUR WORKS is the most easily accessible hydrothermal area in the Park. It is probably part of the central vent system of ancient Mt. Tehama which is described at No. 7. A short paved trail leads to the sputtering hot springs, steaming fumeroles and hot bubbling mud pots. For your own safety be sure to stay on the trails in any of the thermal areas. Slippery clay and thin crusty coverings could lead to a dunking in scalding hot water and mud. Most water in the thermal areas of the Park contain sulphurous or sulphuric acid, so avoid getting it on your clothes. The odor is mainly that of hydrogen sulphide. Much of the white clay is tinted yellow, tan or pink by mineral impurities, chiefly iron oxides. The name Sulphur Works was first used in 1865 when efforts were made by T. M. Boarman and Dr. M. Supan to develop the sulphur and clay potentialities of the area. This land was filed upon originally as a mining claim but was actively used only for the tourist trade beginning about 1940. Some of the non-acidic thermal water was used for hot baths. The property was acquired by the Federal Government in 1951 and added to the National Park to be used as a natural thermal area exhibit. (0.3 mile) In early summer the flowers along the road for the next mile or two, are spectacular. Yellow balsam root (with arrowhead-shaped leaves), mules ears (with similar blossoms), and blue stickseed, which looks like forgetmenot, are the most showy. In late summer tall stalks of false hellebore and yellow senecio are common. (0.1 mile) [Illustration: MULES EARS (yellow)] [Illustration: BALSAM ROOT (yellow)] [Illustration: BLUE STICKSEED] [Illustration: SENECIO (yellow)] 6 ELEVATION 7,000 FEET. Just ahead is a magnificent specimen of western white pine. Being one of the white pine group, it has five needles in a bundle. Its cone is about ⅓ the size of its near relative of lower (Transition Life Zone) elevations, the sugar pine. Its limbs grow far down on the trunk because they get plenty of light for the manufacture of food. Shading in dense forests causes a sloughing off of lower limbs, resulting in natural pruning. (0.4 mile) [Illustration: WESTERN WHITE PINE (five needles) Mature Cone, 6 in. Young Cones and Foliage]