NARRATIVE. 19 



following account from the Professor, of the forest trees about 

 Niagara, illustrated by specimens gathered the day before on the 

 spot : 



"1. Coniferce, (pine family,) remarkable for the apparently whorled 

 arrangement of their branches, and for their evergreen leaves ; in most cases 

 they form hard cones, but one has soft, berry-like fruit. The seeds are 

 naked, winged, resting on the scales. The leaves are peculiar, the nerves 

 not being spread, but often gathered into compact bundles. The Coniferce 

 existed at a very early geological epoch. This was the first family that 

 became numerous after the ferns. Their remains are easily recognized 

 under the microscope by the circular disks on their wood-cells. 



" 2. Sterile flowers grouped together, in spike-like branches, forming 

 catkins ; fertile flowers surrounded by a cup. They all belong to temperate 

 climates. Gen. QUERCTJS (oak,) characterized by their fruit, and by the 

 fact that the female flowers are scattered, and the stameniferous flowers 

 form bunches. There are more than forty species in the United States.' 

 Gen. CASTANEA, (chestnut,) allied to the oaks, but the fruit surrounded 

 entirely by the cup (burr). There are two species in the United States. 

 Gen. OSTRYA, (hop-hornbeam,) only one species. Gen. CARPINUS, (horn- 

 beam,) fruit supported by flat leaf. May be distinguished from OSTRYA 

 by the more prominent ribs, and less deeply marked serratures of the leaves. 



" 3. AmentacecB ; both kinds of flowers in catkins. Gen. BETULA, 

 (birch,) distinguished by the shape of its catkins, which are long and cyl- 

 indrical, and its winged fruit. Gen. POPULTJS, (poplar,) seeds in a pod, 

 very minute, and surrounded by down. P. tremuloides (American aspen,) 

 like the other species, has the leaf-stalk very much compressed, hence the 

 tremulous motion of the leaf. 



" 4. JiKjlandea, fruit with an external soft husk, the nut separating into 

 two halves. There are two genera of this family in the United States : 

 JUGLANS. All have compound leaves, that is, each leaf is divided into 

 leaflets. Two species, black walnut and butternut, the latter distinguished 

 by the silkiness and whitish color of the underside of the leaf. CARYA, 

 the nut does not divide so well as in JUGLANS, but the husk is divided and 

 falls off in pieces, which is not the case in Juglans. At Oeningen, in Swit- 

 zerland, are found fossil hickories. The trees of the tertiary epoch of 

 Europe correspond to the species existing at present in this country. 



" 5. Oleacece, (the ash family,) leaves like those of hickory, but the large 

 lateral nerves do not run to the points of the serratures, as in the hickories. 

 Fruit in bunches, with dry capsules. Flower in the ash, without corolla. 



