2-t HOUGH'S AMERICAN WOODS. 



A second class of Flowering Plants and comprising the rest of the group is the 

 Endogenous or Monocotyledonons Plants, characterized by having stems in which 

 the wood occurs as threads or bundles running through a cellular, pith-like tissue 

 so that a transverse section exhibits the wood as dots and not in concentric rings. 

 Leaves mostly parallel- veined. Embryo with single cotyledon, or rarely two, 

 and then alternate and unequal. Parts of the flower generally in threes. In 

 southern United States and elsewhere in or near the tropics trees are found, such 

 as the Palms, etc., which belong to this class, but none we have to do with at 

 present. 



Exogenous plants are subdivided into two well-marked groups or 

 sub-classes Angiospermce and Gymnospermce. The former includes 

 by far the greater part of the Flowering Plants, and most of the 

 species represented in " American Woods " are representatives of it. 



ANGIOSPER1VLE. 



Flowering, exogenous plants in which there is a complete pistil - 

 with stigma and closed ovary containing ovules which develop into 

 seeds at maturity. This sub-class comprises many groups of plants 

 known as Orders, and such as are represented by plants which attain 

 the dimensions of trees, within the limits of the United States, we 

 propose to consider in the following pages : 



ORDER RHAMNACEJE : BUCKTHORN FAMILY. 



Leaves simple, mostly alternate and with stipules small or wanting. Flower* 

 small, often polygamous and sometimes dioecious ; sepals valvate in aestivation, 

 small, distinct, concave and involute in the bud or wanting ; stamens as many as 

 the petals and opposite them, inserted with them in the edge of a perigynous 

 disk lining the calyx-tube, short and sometimes connected with the lower part of 

 the ovary ; pistil solitary, with mostly superior ovary, 2-5 celled, each cell with 

 a single erect anatropous ovule; stigmas 2-5. Fruit a drupe or pod with one 

 seed in each cell and not arilled ; embryo large with broad cotyledons and sparing 

 fleshy albumen. 



Order represented by small trees and shrubs of warm and temperate countries, 

 with slightly bitter juice and often nauseous or purgative fruits. 



GENUS RHAMNUS, LINNAEUS. 



Leaves mostly alternate, pinnately veined, entire or dentate, petiolate, condupli- 

 cate in vernation ; stipules small and deciduous. Flowers small, greenish, in 

 axillary racemes or cymes, polygamous or dioecious ; calyx campanulate, the 

 tube lined with the disk, 4-5 cleft, the lobes keeled within and deciduous ; petals 

 small, with short claw, more or less notched at apex and turned in around the 

 stamens, deciduous ; stamens with very short subulate filaments and introrse 

 2-celled anthers opening lengthwise ; pistil free, with 2-4-lobed stigma and 2-4-celled 

 ovary, each cell containing a solitary, erect, anatropous ovule. Fruit a globose 

 or oblong, blackish, berry-like drupe, with fleshy epicarp, and containing 2-4 

 cartilaginous, 1-seeded nutlets; seeds longitudinally grooved on the back. 



Trees and shrubs of considerable economic importance, and the name, Rhamnus, 

 is the classical Greek name, pdfivos, of the European Buckthorn. 



