PHANEROGAMIA : FLOWERS. 391 



by many Solanece, the generality of the Grasses, the Silenacece, and 

 the Cruciferce. 



3. The conjunction of the circumstances described under 1. and 

 2. produces a form in which exists a short raphe ; hence the chalaza 

 and point of attachment do not coincide, while at the same time one 

 side of the seed- bud remains undeveloped, so that here also a line 

 drawn from the chalaza through the centre of the nucleus up to 

 the nuclear papilla is curved. This form is termed semi-curved 

 seed-bud (gemmula hemitropa) : as accompanying the simple 

 bud-integument it is peculiar to the Labiates and Boragi7iaceae, as 

 accompanying the double bud-integument, to the Leguminosa. 



4. When a seed-bud is very much elongated, a curve is formed 

 in its middle during its development, so that it appears curved in a 

 horse-shoe form. Here the point of attachment and the chalaza 

 coincide ; the nuclear papilla and the point of attachment lie side by 

 side. A line drawn through the middle of the nucleus is curved, 

 but the two sides of the seed-bud are parallel and equally developed. 

 If the seed-bud is confluent in the curvature, it is called an arched 

 seed-bud (gemmula camptotropa\ as in the Potamogeton and Gal- 

 phimia ; if it is not confluent, it is called a horse-shoe-formed seed- 

 bud (g. lycotropd] : according to Griesbach this occurs in many 

 Malpighiacece. 



5. In some few cases, after the formation of -the seed-bud is 

 complete, an additional bud-integument is produced, which more or 

 less entirely envelopes the seed-bud : this is termed an arillus 

 (in Hellenia ccerulea) ; it of course bears no part in the curvatures, 

 which are complete at the period of its origin. 



Malpighi, in his immortal works, laid the foundation for the study of 

 the structure of the vegetable seed-bud ; but his successors added nothing, 

 and neither used nor understood what he had taught them. Treviranus, 

 in his account of the development of the embryo, certainly did nothing to 

 advance the knowledge of the structure of the seed-bud ; he did not follow 

 up that which Malpighi had done, and he overlooked that very important 

 part of the seed-bud, the embryo-sac. It was Robert Brown who, in 

 1826*, first gave the true history of an unimpregnated seed-bud in 

 Kingia australis. Brongniart f gave some useful contributions. Mirbel J 

 subsequently investigated the history of the unimpregnated seed-bud, in 

 which he gave most interesting explanations, but promulgated a totally 

 incorrect view of the formation of the integuments, which, although long 

 since refuted by Robert Brown and Fritsche, is set forth, i. e. copied, 

 still in Link's Elem. Phil. Bot., ed. 2, vol. ii. p. 79, and even in much more 

 recent works, easy as it is to make the observation in any Lily or 

 Passion-flower, since nothing more is required than a simple microscope, 

 magnifying some twenty times, and a couple of not particularly fine cross- 



* King's Voyage, Appendix, " Botany." London, 1826. 



f Mem. sur la Generation et le Developpement de 1'Embryon dans les Vegetaux 

 Phanerogames. Paris, 1827. 



\ Rech. sur la Struct, et les Devel. de I'Ovule Veget, lu a 1'Acad. des So., Dec. 

 1828, et Add. aux Nouv. Recherches, &c., lu a 1'Ac des Sc., Dec. 1829. 



c c 4 



