144 On the supposed Antheridia of Rhamnus. 



originally composed. This granular matter, there can be little 

 doubt, is to be considered as a resin, with the characters of which, 

 both physical and chemical, its characters correspond. 



Conclusions. — The corynidia of Grisebach differ from true 

 antheridia in the following particulars : — ■ 



1. They are not developed from a single, special mother-cell, 

 differing in form and contents from those surrounding it, as in 

 the case of the true antheridia ; but are merely buddings-out of 

 the tissue of the stipule, and consist even in their earliest condi- 

 tion of several cells. 



2. They possess at no period of their growth a central cavity 

 lined by a membrane. 



3. They do not discharge their contents, when mature, by 

 dehiscence, but simply shrink up and wither. 



4. The most careful observation fails to detect any structures 

 which resemble, in the slightest degree, the antherozoids of the 

 higher Cryptogamia, or which correspond to the "long-tailed 

 globules enclosed in minute spherical cells " described by Grise- 

 bach. 



There seems to be no reason to suppose that the corynidia ai'e 

 at all connected with reproduction ; the function which may be 

 assigned to them with the greatest appearance of probability 

 is that of the secretion of the resinous material, which is so im- 

 portant an auxiliary in the protection of the rudimentary organs 

 of the leaf-bud from external influences. 



EXPLANATION OF PLATE III. A. 



Fig. 1 . (All the objects are represented of the same relative size, as mag- 

 nified about twelve times.) a, a rudimentary leaf with its stipules. 

 The median depression which intervenes between its folded mar- 

 gins may be already distinguished, b, the same in a more ad- 

 vanced condition, viewed from the right side. There is as yet no 

 indication of corynidia. c, here the two corynidia are seen in the 

 space between the leaf and stipule, and projecting over the inner 

 margin of the latter, d, more advanced condition, in which the 

 leaf has arrived at the greatest length to which it attains while 

 enclosed in the bud, but the stipules are considerably shorter. 

 Numerous bunches of corynidia are observed occupying various 

 positions on the median thickenings of the stipules, e, later stage, 

 in which the stipules which now equal or exceed the leaf in length, 

 have lost their corynidia and have become brown and horny at 

 their upper part. 



Fig. 2. (Magnified about ninety times.) a, part of the inner margin and 

 anterior surface of a stipule f ths of a millim. in length. At the 

 upper part is seen a corynidium in its earliest condition, viz. as a 

 nipple-shaped budding-out of the middle layer of cells. Below 

 are seen two other corynidia more advanced, b, a mature cory- 

 nidium. c, a niarcescent corynidium. 



