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HARDWICKE'S SC IE N CE -GO SSIP. 



[March 1, 1SG9. 



BOTANY. 



Ferns. — The twelfth volume of the Gardener 's 

 Magazine commences with the new year, and the 

 first monthly part contains fourteen excellent wood- 

 cuts of species of Adiantum, illustrative of consecu- 

 tive papers on that genus. The part contains, besides, 

 a mass of useful information on garden matters. 



Gall-bearing Plants. — A second list of British 

 Gall-bearing plants is published in the Entomologist's 

 Monthly Magazine for February. 



The Specific Differences between Potentilla 

 tormenUlla and P. reptans. — I hope Mrs. Watney 

 will pardon me for saying that I am afraid the 

 diagnoses of these two plants, as given by her in the 

 last number of Science- Gossir — in fact, any de- 

 scriptions taken from existing botanical works — are 

 not yet sufficiently definite to enable us, at once, to 

 draw a line between the two species ; and that the 

 query respecting them in " B.'s " excellent article, 

 " Why," remains still, in point of fact, unanswered ; 

 for the very nature of the question shows that 

 doubts had arisen in the writer's mind whether 

 the differences already recognized and described in 

 books were sufficient to justify the separation of 

 them into two species. The characters which Mrs. 

 Watney gives are, no doubt, quite sufficient to dis- 

 tinguish the two extreme forms from one another : 

 indeed, they are so very different in size, in the 

 shape and size of the flower, in the appearance of 

 the radical leaves especially, and in the situations in 

 which they are found, that they arc known at a 

 glance ; and, seeing only these extreme forms, one 

 would scarcely dream of suspecting that they could 

 be anything but specifically distinct. But no sooner 

 do we try to write downjthe distinctions on paper than 

 our difficulties begin. Mrs. Watney herself observes 

 that we often find tormentilla with five petals, and 

 reptans sometimes with only four. She further 

 says, " Potent ilia tormentilla has an ascending 

 dichotomous stem." This character, however, is by 

 no means constant ; and Babington himself describes 

 the stem as " procumbent or ascending," putting 

 the procumbent character first. Again, " P. tormen- 

 tilla has temate leaves." The lower leaves, however, 

 of P. tormentilla arc, according to Babington, 

 quinate, like those of reptans, and I know that when 

 the plant becomes luxuriant, growing somewhere 

 else than on dry heaths, the upper leaves even 

 become sometimes quinate, and stalked instead of 

 sessile. The characters of these two plants differ 

 much in different places, and probably Mrs. Watuey 

 has no difficulty in distinguishing them in her 

 neighbourhood; but where I live they are the most 

 perplexing plants I know, and I can at any time 

 during the summer gather specimens that I am 

 quite unable to refer positively to either species. I 



find large round flowers on the hedge-banks, appa- 

 rently of reptans ; but when I come to gather them, 

 they have the small, often temate foliage of tor- 

 mentilla ; and I find small square flowers of what 

 appear to be tormentilla, but when I pull the plant 

 up, it is rooting at the joints, like reptans ; in short, 

 we have every conceivable intermediate form ; and 

 the only conclusions I have hitherto been able to 

 arrive at are that either they are not true species, 

 or that they hybridize very readily, or that some 

 fixed character has still to be found by which they 

 may be distinguished. — Robert Holland. 



Scolorendrum Ceterach. — "Davis's Botano- 

 logy," 8vo., 1813, p. 99, says this fern was fast 

 disappearing about Holyhead, being used as bait 

 for rock codfish. Can any one inform me how it 

 is used ?—JS. M. P. 



"Scurvy-grass" (p. 43).— In my edition of 

 Hooker & Arnott's "British Flora," published in 

 1S50 {sixth edition), the Cochlearia officinalis is 

 said to be an annual or perennial.— S. M. P 



Alder Leaf-buds.— I have perused Mr. Hep- 

 worth's paper on leaf-buds, in your February number, 

 with much interest ; however, he makes but little 

 allusion to the Alder {Alnus glutinosa). This tree, 

 to my thinking, has the most beautiful of leaf-buds ; 

 they are of a rich purplish-red colour, aud in general 

 outline not unlike the W T hite Beam, but are consi- 

 derably longer, and much thicker at the extremity. 

 In March, before the buds are expanded, this tree 

 presents a striking appearance, with the brownish 

 catkins waving in the wind, and is then perhaps 

 the most beautiful of our indigenous trees. — /. F. 

 Robinson. 



The Shamrock.— As the 17th of March— the 

 day dedicated to Ireland's patron saint— is ap- 

 proaching, I might perhaps be allowed to mention, 

 that in the oft-renewed discussion as to what plant 

 is the true shamrock, there has been no mention of 

 Trifolium minus ; at any rate, I have not seen this 

 species alluded to in connexion with the Shamrock. 

 The Celtic portion of the population are enthusi- 

 astic, here as elsewhere, in honouring their saint's 

 day, and in displaying the national emblem on 

 their persons on that anniversary ; but I have never 

 seen any plant worn as the Shamrock but Trijolium 

 minus. I can only speak for this end of the island ; 

 but if they do wear the Trifolium repens generally 

 over the country, as is stated, we northerners ought 

 to take some credit to ourselves for superior taste. 

 Any one who compares the foliage of these two 

 trefoils, will see that the T. minus is much the more 

 elegant plant. I should like to know if T. repens is 

 really the plant worn in the south and west of Ire- 

 land. — S. A. S., Belfast. 



