AND THEIR GERMINATION. 407 



JvMcaginem. — The germination of Triglochin palustre agrees with that of Arum, show- 

 ing no trace of the endorhizal character ; but after the radicle has protruded, a slight 

 ridge forms, which marks its junction with the cotyledon, and is produced by the base of 

 the cotyledon ; and this gives the radicle in some degree tlie appearance of having been 

 endorhizal. 



Typhacece. — Repeated examination failed in showing any traces of the endorhizal 

 character in Typha latifolia, the germination of which is much like that of Butomus, in 

 the cotyledon becoming elevated on a short cauliculus, which is distinctly separated from 

 the radicle by a slight ridge, and it agrees with it also in the position of tlie fii-st leaf of 

 the plumule. A fringe of minute radicles gives it the appearance of being endorhizal, 

 and renders the examination difficult unless made in water. Richard's figures do not 

 represent it as endorhizal *. 



AracecB. — It was after repeated unsuccessful attempts that the seeds of Arum macu- 

 lattmi and Dracuncukis germinated, and neither of them proved endorhizal. At fii'st 

 there is no distinction between cotyledon and radicle (fig. 16), and subsequently only a 

 faintly marked ridge shows the junction between tliem (figs. 17 & 18) ; this consists of 

 the base of the cotyledon, and is seen at the bases of the succeeding leaves (fig. 19). In 

 A. Dracunculus the first leaf of the plumule is alternate ■\vith the cotyledon, being directly 

 away from it ; but A. maculatum does not produce its first leaf tUl after it has formed a 

 small cormus, and in the meantime its cotyledon has withered. Supposing therefore 

 the cormus in the latter to develope rather earlier than the cotyledon, so as partially to 

 envelope it on its dorsal side, or only to form a concave tuberosity beneath it, then it 

 might be compared with the embryo of Zosteracece. 



Falniacece. — The germination of Fhcenix dactylifera agrees with that of the Aracea 

 and lAUacecB, except that it protrudes its radicle Uke a Commelyna, forcing the embryo- 

 tega away in much the same manner f ; a shallow furrow, extending the whole lengtli of 

 the cotyledon, shows its marginal side, and at its base, close to the radicle, is the opening 

 for the plumule, looking like a small scar. It is, however, if pervious, so minute, that 

 the plumule escapes by an artificial opening, sometimes through the back of the coty- 

 ledon, but often through the furrow, in consequence of the tissue being thinner. Taking 

 this furrow as a guide, the first leaf of the plumule is directly away from the coty- 

 ledon. 



Ziliacece. — Smilaci/na, Funkia X, Asparagus, and Allium, aU agree in having the primary 

 radicle exorhizal, and the first leaf of the plumule directly away from the cotyledon. 

 Asparagus has the plumule sheathed by a stipulary process of the cotyledon, as in Iris 

 and Canna ; it is fovmd on the inner side of the plumule, and becomes, in favourable cir- 



* Ann. (lu Museum d'Hist. Nat. torn. xvii. pi. 5. figs. 8, 9. 



t About ten days after germination has commenced, the cuticle at tlie apex of tlic radicle sometimes exfoliates in 

 minute irregular scales, having in some degree the appearance of a commencing coleorhiza ; but the same kind of ex- 

 foliation soon takes place from the whole surface of the elongated cotyledon, which becomes an inch or more in length, 

 and therefore, I believe, is not at all analogous to a coleorhiza. 



X One of the species of this genus is remarkable for a triple plumule, the parts of which, growing during germina- 

 tion, produce a singular appearance. It is in cultivation in the Botanic Gardens, Chelsea. Before germination the 

 plumules are enclosed within the fissure, and all spring from one point. 



k 



