834 



SCIENCE. 



[N. S. Vol. XII. No. 309. 



Lower Austral Zone as generally recog- 

 nized.* In other words they have a lati- 

 tcdinal, as well as altitudinal, extra-zonal 

 extension. Yet because of their much 

 wider distribution and greater abundance 

 within the proper limits of that zone, they 

 are to be regarded as essentially Lower 

 Austral species. 



This majority becomes, however, a small 

 minority and the percentage is reduced to 

 about twenty-five, if we exclude species 

 whose northward extra- zonal range extends 

 only as far as eastern Maryland, Delaware 

 or southern New Jersey. When we con- 

 sider how largely the Carolinian flora of 

 this latter section is diluted with Austro- 

 riparian forms, almost to the obscuring of 

 its true zonal relationship, we can not at- 

 tach very great weight to the occurrence 

 here of axiy particular Lower Austral spe- 

 cies. Or, better expressed, the extension of 

 euch a species into the heart of the Appa- 

 lachiau region must be regarded as more 

 significant than its occurrence in the Coastal 

 Plain no farther north than southern ISTew 

 Jersey. 



Of that large minority of Lower Austral 

 species of the Appalachian region which 

 exceed the general zonal limits in altitude 

 but not in latitude, the following is a pre- 

 liminary and, doubtless, very incomplete 

 list: 



Erianthus alopecuroides. 



Erianthus brembarbis. 



Erianthus coniortus. 



Ohrysopogon. nutans var. Li7incBanua . 



Paspalum longipedunculatum. 



Paspalam purpurascens. 



Panieum gibbum. 



Panicum longipedunculatum. 



Triodia Chapmani. 



Uniola longifolia. 



*The Austro-riparian Area, as defined by Mer- 

 riam in various papers (recently in Bull. 10, Div. 

 Biol. Survey, U. S. Dept. Agric. ) reaches its most 

 northern limits at the mouth of Chesapeake Bay; in 

 extreme southwestern Indiana, southern Illinois and 

 southeastern Missouri ; and in southeastern Kansas. 



Arundinaria macrosperma. 



Cyperus echinaius ( C. Baldwinii. ) 



Lilium caroUnanum. 



Ulmus alata. 



Asimina parviflora. 



Cebatha Carolina ( Cocculua). 



Sarraeenia flava (var. oreopMla). 



Parnassia grandifolia. 



Deaumnria barbara. 



Morongia angustata {Schrankia). 



Baplisia alba. 



Psoralea pedanculaia. 



Berchemia scandens.* 



Vaecinium arboreum. 



Oelsemium sempermrens.* 



Phlox ainmna. 



Oallicarpa americana. 



Yatesia laete-virens {Oatesia).* 



Melothria pendula. 



ElepJtantopus tomentosus. 



Ghondrophora virgata [Bigelovia). 



Aster purpuratus {A. virgatus). 



Pluehea petiolata. 



Antennaria solitaria Rydberg {A. plantaginifolia 

 var. monocephala Torr. & Gray). 

 . Silphium composUum. 



Tetragonetheca helianthoides. 



Coreopsis auriculata. 



Coreopsis major ( C. senifolia). 



Helenium nudiflorum. 



The presence, at an elevation of 300 meters 

 or more, of this considerable number of 

 Austro-ripai'ian species which nowhere else 

 venture beyond the limits of their life zone, 

 is, on the whole, the most noteworthy fact 

 in regard to the Lower Austral element in 

 the highland flora of the Southern States. 

 Species of this category would appear to 

 possess less general tendency to exceed their 

 zonal limits than do those which range 

 farther northward, and this enhances the in- 

 terest of their occurrence in the mountains. 



We now come to the difficult question of 

 the probable past history of the Lower Aus- 

 tral plants which occur to-day in the Appa- 

 lachian region. Are they relics of a floi-a 

 once more widely distributed there, or are 

 they the vanguard of an invading army 

 from lower altitudes and latitudes ? Al- 



* Occurrence in the Appalachian region as above 

 defined somewhat doubtful. 



