PLANTS OF THE SAN BERNARDINO MOUNTAINS 171 



SELAGINELLACEAE 



Selaginella Bigelovii Underw. Bull. Torr. Club 25: 130. 



Abundant in the shelter of stones and shrubs, and in rock crevices, in the 

 Lower Chaparral Zone. 

 Selaginella Watsoni Underw. Bull. Torr. Club 25: 127. 



Frequent in crevices of rocks in the Hudsonian and Alpine Zones, and in 

 the Hudsonian island in Snow Canon. 



ISOETACEAE 



Isoetes Bolanderi Engelm. in Parry, Am. Natur. 8: 214. 



Formerly in the shallow stream which drained Bear Valley, which is now 

 deeply submerged by the reservoir. Probably extinct ; not otherwise known 

 in southern California. 



PINACEAE 



Pinus CouUeri Don, Linn. Trans. 17: 440. Big-cone Pine 



Irregularly distributed, in large or small groups, throughout the Transi- 

 tion Zone. A tree 40-60 feet high. 

 Pinus flexilis James, Long's Exped. 2: 35. Limber Pine 



Near the summit of San Gorgonio Mountain between 10000-12000 feet 

 altitude, and characterizing the Hudsonian Zone; also in the Hudsonian 

 island of Snow Canon, at 6500-7000 feet altitude. A tree 15-30 feet high; 

 often prostrate at its upper limits. 

 Pinus lambertiana Dougl. Trans. Linn, Soc. 15: 500. Sugar Pine 



Scattered, mostly singly, throughout the Transition Zone, preferring the 

 moister and richer soils of flats and ravines. The largest tree in these moun- 

 tains is a Sugar Pine of more than 7 feet diameter growing near Strawberry 

 Flat. This species attains a height of 100-200 feet. 

 Pinus monophylla Torr. & Frem. Frem. 2d Rept. 319, t. 4. Pinon 



Common in arid soil in the Pinon Zone, of which it is the characteristic 

 tree. A short-trunked tree 1.5-35 feet high. 

 Pinus murrayana Balf. Rept. Oreg. Exped. 2, t. 3. Tamarac Pine 



Common in the Canadian Zone, of which it is the characteristic tree. 

 A spreading tree 50-75 feet high. 

 Pinus ponderosa Dougl. in Lawson, Man. 355. Yellow Pine 



The dominant tree in the open coniferous forest of the Transition Zone, 

 and passing into the Canadian. A massive tree, 100-150 feet high. 

 Pinus ponderosa Dougl. var. Jeffreyi Vasey, Rept. U. S. Comm. Agric. 1875, 179. 



Black Pine 



Throughout the Transition forest, much less abundant than the species 



and usually found in flats or near the borders of meadows. A smaller tree, 



50-75 feet high. 



Pinus tuberculata Gordon, Journ. Hort. Soc. 4: 218, t. Dwarf Pine 



Forming a belt nearly half a mile wide, on the arid southern face of the 



mountains between City and East Twin Creeks, at 3500 feet altitude, in the 



Upper Chaparral Zone. The southern limit of the species, and its only 



known occurrence in southern California. Arborescent in habit, but only 



5-15 feet high. 



