92 BOTANY. 



superior. Trees or shrubs Avith alternate, stipulate, or exstipulate leaves. 

 Natives chiefly of temperate climates. The order has been divided into the 

 following sub-orders : 



Sub-order 1. Cupuliferce, the Oak Family. Trees or shrubs with alter- 

 nate and simple straight-veined leaves, deciduous stipules, and monoecious 

 flowers ; the sterile in catkins (anients or capitate clustered in the Beech), the 

 fertile solitary or clustered, furnished with an involucre which forms a cup or 

 covering to the one-celled, one-seeded nut. Ovar}^, two- or seven-celled, with 

 one or two pendulous anatropous ovules in each cell, but all the cells and 

 ovules, except one, disappearing in the fruit. Calyx adherent to the ovary, 

 the minute teeth crowning its summit. Seed with no albumen, filled Avith the 

 embryo; cotyledons very thick and fleshy ; radicle short, superior. Examples: 

 Quercus, Castanea, Fagus, Corylus, Carpinus, Ostrya, Lithocarpus. All of 

 these, with the exception of the last, have North American species. In oaks 

 (Quercus) North America is especially rich, the northern and middle 

 States alone possessing twenty species, not to mention numerous others pecu- 

 liar to the south and west of the continent. Some of the southern species, as 

 the Live Oak (Q. virens), have evergreen leaves. Of Castanea there are 

 three species in the United States : the common Chestnut (C. vesca), the 

 Chincapin (C. pumila), and a still smaller species, C. nana. The common 

 American Beech is Fagus ferruginous. There are also the Hazelnut (Corylus 

 amcricana and rostrata), the Hornbeam (Carpinus americana), and the Iron- 

 wood (Ostrya virginica). 



Sub-order 2. Plataneoi, the Plane Tribe. Flowers in globose catkins ; 

 stamen one, with scales ; ovary, one-celled ; style, thick and subulate ^ ovules, 

 solitary or in pairs ; suspended, orthotropal : fruit consisting of compressed 

 clavate nuts, terminated by a recurved style : seeds one or two, pendulous, 

 albuminous : radicle, inferior ; leaves palmate or toothed, and stipulate. 

 Natives chiefly of temperate regions. The principal genus in this family is 

 Platanus, represented in the Old World by P. orientalis, the Plane tree, and in 

 the New by P. occidentalis. Button-wood, or Sycamore. 



Sub-07'dcr 3. Balsam ißticc, the Sweet-Gum Tribe. Flowers with 

 verticillate bracts or minute scales ; anthers, numerous ; ovary, two-celled ; 

 ovules 00, amphitropal : fruit consisting of two-celled capsules, united together, 

 so as to form a hard cone : seeds usually numerous, winged, albuminous ; 

 radicle superior ; leaves stipulate. Balsamic trees natives of tropical and 

 warm regions. The characteristic genus of this family is Liquidambar, 

 embracing three species, two Asiatic and one North American. The latter, L. 

 styraciflua. or sweet-gum, is abundant in the south-eastern portion of the 

 continent. 



Sab-order 4. Betidineoi, the Birch Tribe. Flowers Avith bracts which are 

 sometimes verticillate : ovary, two-celled ; ovules solitary, pendulous, 

 anatropal : fruit membranous, indehiscent, forming a sort of cone ; seeds 

 pendulous, radicle superior, leaves Avith deciduous stipules. Natives of 

 temperate and cold regions in Europe, Asia, and America, and extending to 

 arctic and antarctic regions. Examples : Betula and xVlnus. Of Betula, or 

 birch, there are numerous species in North America ; the most important 

 92 



