. The distribution of vegetation in the United States, as related to climatic conditions. Phytogeography. CORRELATION OF DISTRIBUTIONAL FEATURES. 561 The area of Arceuthohium is therefore closely similar to that of Pinus contorta, with the exception of its absence from the northern Pacific coast. The area of the mistletoe (plate 29) has been drawn in a more generalized manner than has that of Pinus contorta (plate 16), because less information is available regarding the occurrence of the former. The climatic extremes for Arceuthohium are very similar to those for Pinus contorta, except with re
. The distribution of vegetation in the United States, as related to climatic conditions. Phytogeography. CORRELATION OF DISTRIBUTIONAL FEATURES. 561 The area of Arceuthohium is therefore closely similar to that of Pinus contorta, with the exception of its absence from the northern Pacific coast. The area of the mistletoe (plate 29) has been drawn in a more generalized manner than has that of Pinus contorta (plate 16), because less information is available regarding the occurrence of the former. The climatic extremes for Arceuthohium are very similar to those for Pinus contorta, except with respect to the high conditions of precipita- tion, moisture ratios, and humidity encountered by the host in the Pacific-coast part of its range. This is a case in which a sap parasite is not able to accompany its host throughout the entire range of the latter, apparently as a result of the operation of limiting climatic con- ditions upon the parasite. The well-known xerophytic character of the mistletoes apparently brings their distributional behavior into accordance with that of other xerophytic plants in their inability to invade regions of high moisture conditions. The only mistletoe that is found in Washington west of the Cascade Mountains is a locally abun- dant form of Arceuthohium douglasii growing on Tsuga heterophylla. TCIt#CII*TVItC Dan m Nemui. rnortviaa â¢Â«â¢Â«Â« (F. S.) Mot D«ts. F. CoiB D«lr«, F. 8. PMTtloUXSWAL SUMOTie*. f. S. NoflMAL Daii.« Muw, coLDcar 14 â¢*«⢠or Yuii [ NORIiM. Mun, VUN PiKCtnTATIOII NORMU D«ILT tflUH, r. S. 0«T« IN LonacsT Nommv Rhimt ItciiiA. F. S D*r» m LONOIST N^ntuii tHrr Pim^o; F. MCAM TOT»l, T»*n Q CVAPORATIOH (UiLT MtAN. , F. S. [2 MoUturc Ratios NOHIIAL P/E, F. S. â Nohmal rr/C, F. S. â NOOMAL P/t, VtAII hwmioitt Normal Hcah, F. 8. sun-shinc Normal Daily Duration. F. S. I MOISTURC-TCHPCRATURC INDICCS Normal P/e x T, F. S., Pmtsiological MrrHoo I Fig. 67. Climatic ext
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectphytoge, bookyear1921
