Xvi INTUOnrCTION. 



and septicidul, when it opens at tlie vcntnil suture, or tlirou'Ji the partitions. 

 When it opens transversely, tlic upper portion fulHng otl" entire, Uke u lid, the 

 deliisecnee is circiiinscissiU'. 



90. A Sllique is a slender two-valved eapsule, with two parietal j)laeentffi con- 

 nected by a ]>ersistent false partition. A short and broad silicjue is a Silicle. 

 These are jicculiar to the Mustard Family. 



91. A Pi/io is the lieshy iudehiseent fruit of the Gourd Family, with the seeds 

 often embedded in the pulpy plaeent:e. 



92. A Pume is the indchiscent fruit of the Apple or Quince tribe, where the 

 cells arc enclosed in the enlarged and He.shy tuijc of the calyx. 



93. A Berry is an indehisceut fruit, with the seeds embedded in soft jiulp. 



94. A Drupe consists of one or more hard or bony cells, called the Puta- 

 men, covered with a fleshy or pulpy coat, called the Sarcocarp; as the Peach, 

 Holly, &c. 



95. An Achcnium is a small, dry, one-seeded, indchiscent fruit, the walls of 

 which do not adhere to the enclosed seed. When these are closely united, it 

 becomes a Caryopsis ; or when the walls are thin and bladder-like, and open 

 irregularly, a Utricle. 



96. A Nut is a dry, iudehiseent fruit, with hard or bony walls ; as the Acorn 

 and Hickory-nut. 



97. A Samara is a dry, indehiscent fruit, with its walls expanded into a wing; 

 as that of the INIaple and Elm. 



98. The collective fruit of the Pine is called a Cone or Strobile. 



10. The Seed. 



99. The Seed is the matured ovule, and contains the Embryo, or the rudiment 

 of a future plant. The outer coat, or Integument^ is called the Testa. It varies 

 greatly in texture, and is occasionally furnished with hairs, which either cover the 

 entire seed, or form a tuft (Coma) at one or both extremities. 



100. The terms employed in describing the ovule are chiefly applicable to the 

 seed. The foramen of the ovule, which is closed in the seed, becomes the Mi- 

 cropyle, and is always opposite the radicle of the embryo. The scar left on the 

 seed by the separation of the cord is the Hilum. It is sometimes enveloped in 

 a false covering, originating, during its growth, from the cord or from the pla- 

 centa. This is called the Aril. 



101. The Testa mcludes either the embryo alone, or an additional nutritive 

 substance, called the Albumen. 



102. The Embryo consists of the Radicle, the Plumule, and the Cotyledons. 



103. The Radicle is the first joint of the stem. In germination, it elongates 

 at one end to form the root, and at the other, from a minute bud [Plumule), to 

 form the stem. It is inferior when it points to the base of the pericarp, and su- 

 perior when it points to its summit. 



104. The Cotyledons are the seed-leaves. The embryo of the Exogenous 

 Plants bears two of these, placed opposite (rarely three or more in a whori), 

 while that of Endogenous Plants bears only one. Hence the former are called 

 dicotyledonous, and the latter monocotyledonous. 



10.5. When the embryo is exposed to the combined influence of air, heat, and 

 moisture, it develops into a growing plant. Tiiis is termed Germination. 



