44 MISC. PUBLICATION 4 2 3, U. S. DEPT. OF AGRICULTURE 



5. Equisetum hyemale L., Sp. PL 1062. 1753. 



A Eurasian species, represented in Arizona by var. californicum 

 Milde, in moist alluvial situations: Coconino County, at Navajo 

 Mountain (Wetherill), Cedar Ranch (MacDougal 394), and Oak Creek 

 (Fulton 7379), 6,000 to 7,000 feet, springy places. Alaska to Cali- 

 fornia, Arizona, and New Mexico. 



7. SELAGINELLACEAE. Selaginella family 



Low, depressed or creeping, leafy terrestrial plants of mosslike 

 habit; leaves (in the Arizona species) arranged spirally in many ranks, 

 imbricate, minute; sporangia borne in quadrangular sessile terminal 

 spikes of modified leaves (sporophylls), axillary, of 2 kinds, the 

 larger ones containing 3 or 4 large megaspores, the smaller ones very 

 numerous minute, reddish or orange, powdery microspores. 



1. SELAGINELLA 



Key to the species 



1. Plants strongly dorsi ventral, all the divisions flattish; leaves unequal, those 

 of the under ranks obliquely imbricate, upcurved and clasping. 



1. S. ARIZONICA. 

 1. Plants not at all dorsi ventral; leaves alike, equally ascending or appressed- 

 imbricate on all sides (2) . 

 2. Stems widely creeping, rooting sparingly throughout (3). 



3. Plants bright green; leaves oblique, 2 to 3 mm. long, subulate-attenuate, 

 distantly short-ciliate, ending in a long, greenish-white, scabrous 

 seta 2. S. underwoodii. 



3. Plants grayish green, the divisions cordlike; leaves closely appressed, 



1.5 to 2 mm. long, ovate-oblong, freely longer-ciliate, acutish, the 



seta obsolete 3. S. mutica. 



2. Stems rigidly ascending or erect, rooting only at extreme base (4). 



4. Leaves whitish-marginate, lance-acicular, evenly attenuate to a very long, 



stiff , yellowish-white seta 4. S. rupincola. 



4. Leaves not marginate, subulate-attenuate to an acutish apex, giving rise 

 rather abruptly to the short whitish-hyaline seta__5. S. neomexicana. 



1. Selaginella arizonica Maxon, Smithsn. Misc. Collect. 72 5 : 5. 1920. 

 Graham, Gila, Maricopa, Pinal, Pima, and Yuma Counties, 2,000 to 



4,500 feet, rocky ledges and cliffs; type from the Santa Catalina 

 Mountains (Shreve in 1914). Western Texas to Arizona and northern 

 Mexico. 



2. Selaginella underwoodii Hieron. in Engl, and Prantl, Nat. Pflanzen- 



fam. I 4 : 714. 1901. 

 San Francisco Peaks, Walnut Creek, and Oak Creek (Coconino 

 County), Pinal eno Mountains (Graham County), Chiricahua Moun- 

 tains (Cochise County), Santa Rita and Baboquivari Mountains 

 (Pima County), 5,500 to 7,500 feet, cliffs and rock ledges. Western 

 Texas to Wyoming and Arizona. 



3. Selaginella mutica D. C. Eaton ex Underw., Torrey Bot. Club Bui. 



25: 128. 1898. 

 Navajo County, probably near Tyencle (Wetherill 536), Grand 

 Canyon, Coconino County (several collections), Chiricahua Moun- 

 tains (Tourney in 1894), 6,500 feet or lower, damp cliffs. Western 

 Texas to Colorado and Arizona. 



4. Selaginella rupincola Underw., Torrey Bot. Club Bui. 25: 129. 



1898. 

 Chiricahua and Dragoon Mountains (Cochise County), Patagonia 

 Mountains (Santa Cruz County), Santa Rita and Santa Catalina 



