, FILICES. 
sobsteataeanetrhythegemnng ig eideb have arrived at 
. The third period of their growth commences. 
he now gradually elongates, but except where it 
ramifies, invariably in a direction el with the axis 
not Of the great vascular fasciculi; and Sprengel is incor- 
circinate, as rect in supposing the buds of the tuberous stem to be 
supposed by involute or circinate, like those of the fronds which ger- 
Sprengel. ninate from it. ‘These, in fact, Gopsist of ‘round ta- 
mez or Tar ago shewn Linneeus to have originated 
miner t = of the tuber wes enni os Cpe 
dium , Willd. Sp. Plant. 110) covered with 
att ag scales,common tomany of these plants. It 
is certain, , that the numerous rere we te of 
ent growth 
ne do not actually 
of the Tartars. 
From the extreme slowness with which both ferns and 
-arrive at an adult state, we not me that 
ch it is well known 
= __begpa f cimmahuinar amueiaeoeermies Stan da 
Lined werd wenneryt With respect to ferns, indeed, 
few of which are necessary to the wants of mankind, 
no observations, as to this circumstance, are recorded. 
In tracing the of the stem of these plants, 
theacctiracy of Malpighi is again manifested ; for, to 
this excellent observer, we owe the first notice of their 
‘structure, Ina 
ven by fat the 
Si a te m4 
iy ied, of the cen- 
But however valuable an 
i of these parts be-when thas exhibited, we have 
an iJlustration of the general stracture of the 
easel pe Weppesee whsets sertivdly chamnirted by 
the naked eye, as & more correct outline, not 
only of: tha geneeal etrnctave; Tut of the relation the 
4 several parts of the stem bear to each other. Some- 
es 8 ea etn is» te 
by too amagnifying er; the su 
i tole: aepeciesited tr-viihsae ae 
clearly delineated, a which seems well il- 
lustrated by the: ‘view given by Des- 
te ac ns section of the ser ofa fern 
aon 0 
ts.* Baledaemetae-mat tire ce nic 
as possible posbible,’ itis mecestaty to'cut the 
seen ag en from the lateral buds. 
@ transverse section of the ‘creep. 
di a i ee spidium filix mas; and Fig. 6 a 
me! 
tsa canal set of that of Davallid canariensi: 
tae the origin. of the buds of these’ plants, it is’ 
. 
VOL. IX, PART 
of these plants, - 
329. 
clear that they originate from the cellular substance of _ Filices. 
the centre swelling, and in a manner forcing the vas- 
= fasciculi to accompany them in a lateral direction. 
. 7. @ The exterior cellular substance, part of 
a , In the stems’ of ob: rk he Se is 
externally converted into a substance of the density of 
PLATE 
CCLIV. 
* horn, which is sometimes furnished with spines, but is, 
for the most part, in young plants, covered with woolly 
scales,each o which i is furnished with a central fasciculus 
probably vascular, issuing from a pore in the surface of 
the stem. These scales serve- partly the purpose of Ssecharine © 
bark, in protecting the e young shoots, and evidently pre- neo 
vent the evaporation of the fluid part of the sweet juice 4); stems of 
which every- where envelopes the germs of the future ferns, 
fronds and stems, which, in our northern climate, remain 
dormant during winter. The central cellular matter 
in ferns (Fig. 7. 6) is not converted into wood, as in de- 
cotyledonous trees, but remains soft and spongy, in the 
at least, till finally absorbed during the ripening 
of the fruit. This substance abounds with a similar sac- 
charine juice, often accompanied with an unpleasant 
astrin . ‘The stem and branches of these plants are Cyjindrical, , 
entirely cylindrical, unless accidentally checked in their and not 
growth by renioval into an unsuitable soil, whereas the conical like 
stem and branches of dicotyledonous trees are invariably ‘¢ west of 
conical, tapering towards the extremity. a 
Fig. 7. and 8. c, The roots in the procumbent species, a 
issuing from the cellular substance, and descending into 
the soil, from the under side of the stem, opposite the 
buds. Each of these shoots, therefore, 
when d form so many distinct panes posted 
the full diameter of the adult stem, and, like t 
tioned by Kempfer, occasionally ‘shooting i in the same 
manner, from stem of s, attain their 
form. It was, I believe, Micheli who de- 
scribed the or covers on the extremity of © a gh 
the roots in certain aquatic plants. Sprengel has § 
observed these covers on the extremities of the fi- fous 
brous roots of ferns; and supposes Sehapiotbe argue 
of absorption analogous with the am- 
rption, in some degre en 
’ pull in the villous coat of the intestinal: canal of ani- 
mals. To us, it would seem ble, however, that 
these covers, like the chaffy scales of the stems and 
fronds, are intended rather to the delicate ex- 
tremities of the absorbent roots, than to perform this 
office themselves. 
Ill. Of the Fronds and parts of Fructification of 
, Ferns. 
Tue buds from which the fronds of these plants are 
evolved, form of the great central tuber from 
which the ster itself is produced. This tuber, in our 
northern climate, is found during winter, surrounded 
with the decayed ati of the fronds of the 
ing season, and cl invested with the woolly scales 
already mentioned. In examining these buds te~ 
ly, we find that it is the superior or frond only 
which is involute, or circimate, sts tt termed : the 
stipes itself extended sey a # straight line 
from its origin within the stem. Aapidiam file 
mas, we have traced the Siretging fasciculi 
within the stem, before the external evelopementof dhe 
fronds ; and this appears evident in some species on cut- - 
ting it neross, when the large central fasciculi of the stem 
appear surrounded with the smaller ones of the stipites of 
former years, (Fig. 7. The reason these are not per- 
apne es thc ecient ohio plte veppttboatet te Fig: 8: 
* Memoires de Institut National, tom. i. p. 478, by Desfontaines. ‘ 
27 
