90 



NySSA BIFLORA Walt. 



A single seed belonging to this species was found. The genus 

 appears in the mid-Cretaceous and becomes abundant in the late 

 Tertiary, the fruits being very common in the lignites of Brandon, 

 Vermont, from which Perkins has recorded no less than seven- 

 teen distinct species. 



None of the foregoing species furnishes any very definite data 

 in regard to the climate of Talbot times, all being wide-ranging 

 forms in the existing flora. Thus the beech ranges from Nova 

 Scotia to Florida, as do some species of grape. The pignut 

 hickory ranges from Maine to Florida and Texas ; the cypress 

 from Delaware to Florida, and the black gum from New Jersey 

 to Florida and Louisiana. 



Judging from the range as above given, we would not expect 

 the climate of this river swamp in Virginia to have been colder 

 than obtains in like surroundings in New Jersey at the present 

 day. Temperatures were probably higher, as they were un- 

 doubtedly more uniform than in the adjacent uplands, the spe- 

 cies all indicating a low, close stand of timber, the gum and cy- 

 press being characteristic swamp forms, the vine a lover of low 

 thickets, the beech and pignut, especially the former, also pre- 

 ferring deep, damp woods. 



Maryland Geological Survey, 

 Johns Hopkins University. 



REVIEWS 



Burgess's Species and Variations of Blotian Asters* 



Here is a notable work notably performed, and one which 

 responds in full measure to a long insistent need. Of all the 

 larger groups of flowering plants in our eastern flora not another 

 one, perhaps, now that enlightenment has dawned in the realms 

 of hawthorn and of violet, has so pressed upon the student its 

 need of re-interpretation as the asters — plants full of allurement 

 and delight to the hopeful beginner, to the systematist recondite 



* Burgess, Edward Sandford. Studies in the History and Variations of Asters. 

 Part II. Species and Variations of Biotian Asters with Discussion of Variability in 

 Aster. Mem. Torrey Club 13 : i-xv + I-419. / 1-108. 15 Mr 1906. Price $3.00. 



