Name honors Johann Peter Huperz (d. 1816), German fern horticulturist and author of a book on fern propagation.

Plants small to medium-sized, epiphytic or terrestrial. Stems clustered, erect or pendent or decumbent, branches all similar, of equal length; roots arising at stem tips, descending through stems to bases, emerging in one basal tuft. Fertile leaves and sterile leaves alike, or fertile leaves gradually to abruptly reduced, persisting after sporangia dehisce. Sporangia in axils of leaves, reniform, bivalvate, on short, slender stalks. Gemmae present, or not. Gametophytes subterranean.

A cosmopolitan genus of about 300 (estimates range from 200 to 400) species found in tropical, temperate, arctic, and alpine habitats·. Ollgaard (1987) divided Huperzia into twenty-two acceptably well-defined groups. His classification is followed in this book. Represented in Hawai'i by three of these groups: the Phlegmaria group (H. mannii, H. nutans, H. phyllantha, and H. stemmermanniae ), the Selago group (H. erosa, H. erubescens, H. haleakalae, H. serrata, and H. subintegra), and the Verticillata group (H. filiformis).

KEY TO THE HUPERZIA GROUPS IN HAWAI'I

1. Plants mostly terrestrial, mostly erect; gemmae present; fertile leaves same size as sterile leaves .................................... 2. Selago group

1. Plants mostly epiphytic, pendent to erect; gemmae absent; fertile leaves in strobili of smaller leaves (2).

2(1). Sterile leaves narrow, 2-4 X 0.1-0.15 mm, lying flat and overlapping stem ............................................ 3. Verticillatagroup

2. Sterile leaves wider, 5-12 X 2-5 mm, spreading and not overlapping stem ............................................ 1. Phlegmaria group