[ 259 | 
XXIX. Evtract from a Memoir on the Origin and Development of Vessels in Mongéc- 
— tyledonous and Dicotyledonous Plants. By Dr. FRANCISCO Frere ALLEWÉO, of 
Rio de Janeiro. Translated and communicated by Joux Miers, Esq., F.R.S., 
F.L.S. $c. | | 
Read January 16th, 1855. 
In 1849 ı began a series of microscopical investigations upon several points of vegetable 
anatomy, among which was one that attracted my chief attention, because of its greater 
novelty,—the origin and development of vessels in the roots of plants. 
In 1851, I read before the Vellozian Society of Rio de Janeiro a short memoir, in 
which the most important facts that I had observed were collected, and which appeared 
to me wholly new to science; at least I have found no record of them in the books 
within my reach. That memoir, being accompanied by drawings, could not then be 
printed, but I afterwards revised it, made it somewhat shorter, added other remarks, and 
suppressed the drawings: in this form it was published in the following year (1852), as 
the “Third Memoir of my Botanical Exercises :” (Trabalhos da Sociedade Velloziana, 
BAUER. v 7 
In the year 1853 I continued the same pursuit, when my attention was not limited 
to the examination of the growth of vessels in germinating seeds, but was directed also 
to that of dicotyledonous plants considerably advanced towards a ligneous state: similar 
observations, extended at the same time to the growth of monocotyledonous plants, 
convinced me that their mode of development was exactly the same as in Dicotyledons. 
This last investigation is not yet completed; it will be of considerable length and 
accompanied by explanatory drawings, so that I know not when it will be finished : but I 
send you now an extract from it, with such details as may be requisite to make the 
drawings that accompany this understood: I am the more anrious to do this, in order to 
learn whether my observations are new, and worthy of the attention of European botanists, 
or whether they are already known or sufficiently exact. 
The vine A. shows the observations upon the growth of a young plant of Sida 
carpinifolia. à 
Fig. 1 (Tag. XXVII.) represents the plant of its natural size scarcely developed, ces 
the epigeal cotyledons still enveloped in the seminal integuments. The caulicle = de 
linear and without any ramifications, that is to say, without any radicular fibres yet formed. 
Fig. 2 shows the same plant much magnified, as observed under ee oe E Tet 
cotyledons are thus seen with their nervures formed of tracheal vessels alone, o 
two constituting the midrib are continuous with those of the caulicle; these are red T 
number, distinct, entire, straight, parallel and equidistant, descending into the c = = 
far as a: the lower portion of the caulicle does not yet exhibit any me us BE 
radicular bulb, b, does not yet show any tendency to form roots. 
VOL. XXI. 
2M 
