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INTRODUCTION TO BOTANY.

nately to both sutures, as is seen in that of Mustard, Radish, Turnep, inc.The form of this gives the name to the order in the class TetradynamiaSiliquosa, as before noticed. Another seed-vessel, differing only in formfrom this, is called a S.iiicdla, which gives the name to the order Sili-culosa. It must be observed that this is in general flat, as in Satin*flower; round, as in Sea Kale ; or like a shield, as in Biscutella ; or heart-shaped, as in Thlaspi, Shepherd's Purse, &c.

Lec.umen (a Pod), This has two valves or external openings in-closing a number of seeds fixed along one suture only. Examp.—TheCommon Pea,

Foluculus. This has one valve only, and opens longitudinally onone side, having the seeds loose in it. Examp.—As is seer, in the podof Asclepias, Dogs-bane.

Drupa has no external opening like the capsule or legumen, andcontains within its substance a stone or nut. This is exemplified in thePeach, Almond, Cherry, &.C.

Pomum differs from the Drupa in containing a membranaceous cap-sule of different cells, in which are placed the seeds. Melon, Apple,Pomegranate, &c, are of this kind.

Strobiics (t Cone). This is a species of seed-vessel composed of anumber of scales lying one over another; as is exemplified in all theCone-bearing trees, Fir, Cedar, &.C

The SF.EDS. These may be considered analogous to the eggsof animals, affording the usual and natural mode of propagation inplants. The different parts of which most seeds are composed are,The Hilum, or Eye, by which it was attached to the pericarp : TheCutis, or Husk : The Corculum, or Embryo of the plant; this con-tains the radicle and plumule: The Cotyledons, or Seed-lobes ;—allwhich parts are essentially necessary to forward the process of vege-tation.

The RECEPTACLE (Receptaculum), the seat of the fructification.This is also divided under the following heads.

The Common Receptacle, containing both flowers and fruit, as in theclass Syngenesia. Calendula, Marigold, Anthemis, Chamomile, are in-stances of this.

This is also styled the Receptacle of the Flower, as in Rubus. Herethe fruit is its receptacle, being below the flower ; the receptacle of thefruit being still below this part also.

It varies also in shape: being flat, as in Dandelion;— conic, as inTeazle; subulate (awl-shaped) as in Mousetail;— -chaffy, as in Rud-bcckia;— hairy, as in Carduus,

It is termed an Umbel, as in Conium and Mthusn, &c.;—a Rachis,(the spike,) as in Scotch Fir;—a Spadix, as in Arum, Cuckoo-pint.