42 



GETHIONEMA MEMBRANACEUM. 



obtained from seeds, which are produced in abundance, and may be sown in the 

 open ground in April. It will grow well in almost any kind of soil, and is well 

 adapted for ornamental rock-work. 



The name given by Dr. Brown to this genus is derived from Ai0co, to scorch, 

 and vn[xa, a stamen ; and is supposed to allude to an apparently scorched or 

 sun-burnt tinge of the stamens : the specific Latin name alludes to the mem- 

 branous appendage to the seed-vessels. The genus contains but few species, not 

 more than ten being at present known, all of which are found in Europe or Asia, 

 none being met with (as far as we know) either in Africa or America, and of these, 

 six have been introduced into this country. The medicinal properties of this 

 genus do not appear to have been examined ; but they are probably stimulant 

 and antiscorbutic, qualities by which the natural order is universally characterised. 

 The order Cruciferse is one of the most natural in the whole vegetable kingdom, 

 and is particularly distinguished by the stamens, four of which are long and two 

 short, and hence called tetradynamons, by the four petals, arranged in a cruciate 

 manner ; and alternate with the sepals. To have six stamens to four petals, 

 instead of four or a multiple of that number, is a curious deviation from the 

 ordinary normal structure of other plants. 



The seeds of this order are also worthy of minute examination, from the 

 curious and singular manner in which the embryo with the radicle is folded upon 

 the cotyledons, and which has enabled Botanists to separate this most difficult 

 and extensive order (containing not less than 98 genera and 980 species, 

 exclusive of varieties) into five sections, and thus to render it more practicable in 

 the hands of the student. As it may possibly be interesting to some of our 

 readers, we here give a brief description of the sections and the peculiarities on 

 which they are founded. 



Section 1. Pleurorhize.*: ; (o=) cotyledons flat, accumbent, radicle lateral, 

 which may be witnessed in the genus Arabis, Mathiola, or common stock. — 

 2. Notorhize^j ; (o||) cotyledons flat, incumbent, radicle issuing from the back. 

 It may be noticed in the genus Hesperis or Dame's violet, a common plant in 

 gardens, or in Sisymbrium officinale. — 3. Orthoploce^e ; (6%) cotyledons condu- 

 plicate, or longitudinally folded, and having the radicle within its folds, as may 

 be observed in the Brassica and Sinapis tribes. — 4. Spirolobe^: ; (o|| ||) cotyledons 

 incumbent and linear, spirally or rather circinately twisted, as in the genus Bunias 

 and Erucago. — 5. Diplecolo be ; (o|||]||) cotyledons twice folded transversely, as 

 in our British plant Subularia aquatica. 



Fig. 1, seed-vessel ; 2, the same divided, showing its two cells and two seeds. 



