Botany and Zoology. 



433 



by Schacht, of late its most strenuous and able defender. The conversion 

 in this case has been accomplished by one of Schleiden's own pupils, viz : 

 by Dr. Radlkofer, who was authorized to announce this result in his me- 

 moir ; and more recently Schacht, having essentially confirmed Radlkofer's 

 views by his own observations, now admits that the pollen-tube exerts 

 merely a fertilizing influence upon a previously existing corpuscle in the 

 embryo-sac, which thereupon forms an investing coat of cellulose, and 

 becomes the germ of the embryo. This particular view, Prof. Henfrey 

 (in Ann. and Mag. Nat. Hist, for Sept., 1856,) claims as original with him- 

 self, and advanced in a paper read before the Linnsean Society last March ; 

 also briefly in the article " Ovule," in the Micrographic Dictionary, pub- 

 lished a year ago, asserting " that the germinal vesicles (or corpuscles) 

 exist in the embryo-sac before fecundation, not as complete cells, but as 

 corpuscles of protoplasm which acquire their cellulose coat after the fertil- 

 ization by the agency of the pollen-tube." But as the exactly analogous 

 fact had been already demonstrated in the case of the spores of Algae, 

 &c.) "the assertion of the opinion" in the present case was very natural ; 

 though the researches referred to may be very important. 



If we rightly understand the statement, Dr. Radlkofer maintains that 

 it is not the corpuscle or vesicle contiguous to the pollen-tube, but a second 

 one, next to the former, which becomes fertilized, and develops the em- 

 bryo, and which accordingly is never in contact with the pollen-tube ; — 

 a view which may readily be harmonized with Tulasne's beautiful re- 

 searches. A. G. 



3. Bentham, Notes on Loganiacece, (in Journal of the Proceedings of 

 the Linncean Society, No. 2.) — A most judicious and thorough revision 

 of this group of Rubiacece with a free ovary, or " a sort of artificial offset 

 from that family," which it becomes necessary in practice to separate. 

 We cite a portion of the introductory remarks, for the special benefit of 

 those who maintain that families, genera, &c, are as really and strictly 

 limited in nature as they are in our systems, i. e., when our systems are as 

 perfect as they practically can be. 



" Our natural orders, with all the improvements they have received 

 from the most philosophical of modern botanists, are yet as dissimilar 

 in definiteness of circumscription and apparent conformity to nature, as 

 they are in extent. Some indeed, including the two most numerous of 

 all, are so well characterized as to admit of no doubt. The Cruciferce, 

 Leguminosce, TJmbelliferce, Compositce, Labiatce, Palmce, Orchidece, Cype- 

 racece, Graminece, and several others, comprehending two-thirds of the 

 known species of plants, are admitted by all botanists without any varia- 

 tion, and although, amidst the thousands of species comprised in each, 

 there may be some one or two which may offer an exceptional character 

 or anomalous structure, indicating some slight approach to other groups, 

 ye' we cannot have the least hesitation as to where to draw the line of 

 demarcation. The Himalayan Meyacarpceas, although polyandrous, are 

 still decidedly Cruciferous, not Capparideous. The distinction between 

 Leguminosce and Rosacece, although so difficult to be expressed in words, 

 is yet so clearly defined, that we find no single genus or species ever con- 

 sidered as intermediate, and, although the passage from the former into 

 Terebinthacece through Copaifera and Connarus be really more gradual, 



SECOND SERIES, VOL. XXII, NO. 66. — NOV., 1856. 



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