464: MR. JOHN MIERS ON A NEW GENUS OF THE BURMANNIACEZÆ, 
they are distinetly observable in other parts of the plant: the stem, composed entirely 
of transparent hexagonal cells, has a medullary cord running up its centre, formed of a 
bundle of spiral vessels, which on reaching the base of the ovary, divides itself into six 
portions, severally following the course of its sulcated furrows, three of them thus pass. 
ing by in close proximity to the placentæ, but without communicating with them ; and 
all are continued along the grooves of the tubular perianth, thus touching the stamens, 
and they extend to the extremities of the six segments of the border: no spiral vessels 
are found in any other parts of the plant. Prof. Henfrey (Linn. Trans. xxi. tab. 2) 
shows the funiele and integument of the ovule of Orchis as being quite cellular and 
destitute of vessels; but I have found spiral threads abundantly in the longitudinal 
placentæ of many Orchidaceous plants; I could find no trace of them in the placentæ 
of Myostoma. The tissues of most of the Rhizogens are said to be deficient of tracheal 
vessels; but they have been detected in some of the Balanophoree. 
The resemblance of the apparently torulose body contained within the seed of Myo- 
stoma to the nucleus delineated by Mr. Robert Brown in the seed of Rafflesia, in the 
Linnean Transactions (vol. xix. plate 25, R. B.), is too remarkable to pass over without 
notice. Bauer, who repeated Mr. Brown’s analysis, and prepared the drawings for that 
memorable memoir, figures the nucleus as he saw it under the most powerful microscope, 
considering it to be a simple cylindrical embryo of homogeneous texture; but under 
the more penetrating observation of Mr. Brown, it was resolved otherwise and as he drew 
it separately in the figure marked R. B. in the same plate: according to his view (/. c. p. 
228), this ** embryo consists of large cells disposed nearly, but not with absolute regularity, 
in two longitudinal series, and so transparent that it may be safely affirmed that there 
is no included body, nor any perceptible difference in the contents of any of the compo- 
nent cells." It was in this manner that I regarded and described, nineteen years ago; 
the nucleus or supposed embryo of Ophiomeris (Linn. Trans. xx. 376, pl. 15. figs. 18, 19). 
Griffiths defined the seed of Thismia (Linn. Trans. xix. 342) as consisting of two in- 
teguments, the outer one being “ celluloso-areolate, fragile and easily separable, the 
inner one extremely slender, membranaceous, scarcely separable, and containing à cellu- 
lose waxy mass (embryo) composed of cells filled with grumous molecules and oily mat- 
ter,” but he gave no figure to explain any further meaning. 
Dr. Lindley, founding his views principally upon the evidence of Brown in regard to 
Rafflesia and Hydnora, and the details he had obtained from Griffiths concerning the 
Balanophoreæ, separated these and all analogous plants from Exogens, on account of 
their “homogeneous or anembryous sporuliferous seeds;" and in his *Elements of 
Botany,' p. 226, he defines the Rhizogens, or Rhizanths, as * wholly or nearly destitute 
of vascular tissue ; and when their seed is fertilized, instead of an embryo being formed, 
the issue is a mass of sporules or reproductive bodies analogous to those which Aoro” 
gens have instead of seeds.” 
This definition was considered by Mr. Griffiths (. c. p. 306), “to be open to the 
gravenlı objections.” He did not oppose the use of the term “homogeneous,” whic gi 
considered correct, but the case was very different when that term was connected - 
the want of an embryo and with a sporuliferous mass: he did not find the appear 
| 
| 
| 
| 
| 
l 
| 
