ee 
—— ee 
as Monthly Botunical Report. ‘[Marel 1, 
nature or office from the subterraneous cotyledons, or such as do not rise out of the earth ; 
and the aythor observes, that cotyledons and vitellus never occur in the same seed. Gaertner 
had himself remarked that there is so little difference between the subterraneous cotyledons 
arid vitellus, that they are, in fact, united by the closest affinity, nature seeming to proceed 
in the formation of these organs by gradual advances from the simple texture of the al- 
bumen, to the more organised structure of the vitellus, and thence to the still more perfect 
cotyledons: so that, in this respect, at least, the opinion of the president does not appear to 
be very different from that of Gertner: The latter, however, supposed the vitellus to be 
destined to afford nutriment to the young plant, at its first germination, which Dr. Smith 
does not allow, thinking it more reasonable to suppose that the albumen,alone is destined for 
this purpese, whilst the vitellus and cotyledons, like the Jungs of animals, appear intended 
for the absorption of oxygen. Thisis illustrated by a reference to the experiments of Dr. 
Priestley, showing how oxygen is absorbed in the dark by the under surface of the leaves : 
so the under side of the cotyledons and vitellus is always turned outwards ; and those that 
do not ascend out of the earth may be favoured, in this operation, by exclusion from light 5 for 
Which purpose the author further observes that the testa of the seeds is frequently of a black 
Colour. But as it is allowed that the alkuminous or nutritious matter, mstead of being 
lodged in’a distinct organ, is so frequently united with the cotyledons, in which cases these 
organs perform the double office of supplying nutriment and absorbing oxygen; So; if we 
consider the vitellus in the same latitude as Gartner has doues, it may be concluded, that, 
In these cases, in which it fills a considerable portion of the testa, the albuminous matter ts 
mixed with the vitelline organization, and the double office performed as in the more perfect 
cotyledons. - If the name of vitellus be confined to the small scate-like organ, as it occurs 
in grasses, where the albumen forms so large and distinct a viscus, it may safely be concluded 
that it does not afford nutriment to the germinating embryo, but is destined for the sole pur- 
pose of absorbing or being acted upoh by oxygen. Dr. Smith’s idea of a Cotyledon is that » 
it is “a vital organ, capable, as fuch, of being stimulated by oxygen, heat, or both, for the 
propulsion of its contents ; while such an albumen is merely a repository of nutritious ve+ 
getable matter, subject to the laws of chemistry alone, and only passively resigning those 
contents to the absorbing powers of the embryo, to which itis attached.’’ It may, bowever, 
be very well made a question, whether the first cermination of the seed is occasioned by 
the propulsion of the fluids towards the embryo, as Dr. Smith imagines, or that the embryo 
by its vital principle first absorbs and propels the fluids into the cotyledon, to be there” 
oxygenated, or to wudergo the necessary changes, and thence returned to the embryo fitted 
for all the purposes of nutrition and the incréase of the youg plant. The latter epinion may 
appear the most probable, if a comparison be made with what takes place in the animal sys- 
tem, in which ibe blood is propelled by the vascular system of the fetus into the placenta 
or cotyledons, for the purpose of being furnished with oxygen and nutritieus particles, 
whence it returns to the fetus. It must be allowed, however, that this analogy is very de- 
fective, fromthe want of any organ similar to a heart, in the vegetableembryo. Upon the 
whole, while we allow the merit of an ingenious and plausible hypothesis to this essay, it is 
very evident that anatomical facts, many experiments, and much patient investigation, are 
still necessary to explain satisfactorily the physiology of germination. 
The sixteenth paper, by William Hunter, esq. secretary to the Asiatic Society, deter- 
mines that the little cakes or lozenges known by the name of Gutta gambir, are not prepared 
‘from the Mimofa catechus as had been suspected, but from the leaves of a species of Nauclea 
here described, figured and named Nauclea gambir.. Two other species of Nauclea, viz,’ 
N. acida, and N. sclerophyl/a, are here characterized and described. 
The seventeenth paper contains observations on several British species of Hieracium, by 
the president. Itis here observed too, that Hieracium dubium, and H. auricula, were ad- 
mitted into the Flora Britaunica, solely on the authority of Mr. Hudson. It having been 
suggested to the auther of that work by a learned friend that he had taken the one for the 
other, he has in this paper defended himself from the supposed error; and for this purpose- 
he has critically and chronologically examined all the Linnean synonyms of both species. 
It appears, by this detail, that the Linnzan names have been misapplied in the Flora Danica, 
the H. dubjum of which work, tab. 1044, is the H. auricula of Linneus and Dr. Smith; and 
Ki. auricuia, tab. 1011, is the true H. dubium—2. It had been suggested to the author of the 
Flora Britannica, that his Hieracium murorum B. was the 2. of Linneus; the mistake is here 
handsomely acknowledged and accounted for.—3. Under Hieracium sy/waticum, the syno- 
‘nyms of Ray, and Gerard emac. as well as Petiver’s t. 15. f. 5. a copy of the latter,. are to 
be removed frem this place to designaté a variety of Cineraria integrifolia: the tale of this 
écecision is unfolded in an agreeable end interesting manner.—4, Hieracium ceriathoides is 
added to the British Flora, on the authority of a specimen gathered inthe Highlands of - 
Scotland by Mr. George Don ; from whom we learn, that it is a plant of common occur- 
rence on the rocks of that country. — - : 
‘The eighteenth paper, by the same, contains specific characters of the decandrous papi- 
jronaceous plauts uf New Hoiland, the genera of which Dr. Smith had before determined — 
"#n the first volume of the Annals of Botany. From this papér may be added to the list of 
i New 
