The "Places on Earth" series of readings by prominent writers visiting the University of California, Davis, will take place during April and May, featuring such writers as Pam Houston and Francisco Alarcon. The series, which is free and open to the public, is sponsored by the campus's English department, program in nature and culture and the College of Letters and Science. In its ninth year, the series focuses on the theme of literary place and nature. Houston, the author of the widely acclaimed collection of short stories "Cowboys Are My Weakness," will open the series at 8 p.m. Tuesday, April 12, in 3 Kleiber Hall. She will read from a new novel. A book-signing and reception will follow. The visiting writers' series also will include conversations with the authors -- in an informal series of wide-ranging discussions with each writer -- at 2 p.m. on the same days as the evening readings. The afternoon programs will be held in Room 912 of Sproul Hall. The rest of the series is as follows, with readings at 8 p.m. in 3 Kleiber Hall: • April 26: Terry Tempest Williams, author of the best-selling memoir "Refuge" and a new collection, "An Unspoken Hunger." • May 10: William Kittredge, author of "Owning it All" and "Hole in the Sky" and writer/co-producer of the award-winning film "A River Runs Through It." • May 24: Francisco X. Alarcon, author of "Snake Poems" and winner of the 1992 American Book Award for poetry, and a UC Davis lecturer in Spanish and classics. Alarcon will appear in a reading/performance with the percussion group The Rhythmagics.