Ronald Coleman begins a beautifully illustrated three-part series on the cypripediums of the United States and Canada. This series is intended to bring an appreciation of the exquisite beauty of this group of native orchids. In this issue Laura Bonnell completes her four-part series on the Dendrobium bigibbum complex and its hybrids and Synda Nelson discusses Paphiopedilum sanderianum and its spectacular hybrids.  These plants aren't small but if you have the space to grow them, their tall inflorescences of multiple flowers are simply stunning.  Rounding out our May issue is an excellent Genus of the Month article by Tom Mirenda on the genus Rhynchostele and Sue Bottom walks us through a very thorough discussion of the use of citric acid pH and alkalinity adjustment of high-alkalinity water sources.