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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



It may be laid to the account of the iiiduatry of Dr. Schwert- 

 schlager that he has discovered in his district and described no fewer 

 than 256 varieties, of which 142 are attributed to R. canina, including 

 R. tomentella, and this without counting some fifty hybrids which are 

 also described and catalogued. 



Dr. Schw^ertschlager's treatment of R. canina is not without 

 interest, and here he departs somewhat from Baker's arrangement. 

 He divides the species into two sub-sections, R. tomentella, which 

 approximate more or less to the Sweetbriars (corresponding to Baker's 

 sub-division Sub-rubiginosae), and Eucariinae or Caninae proper, the 

 latter being again sab-divided into four divisions, or rather two primary I 

 divisions, each of which is again sub-divided. In the first division the 

 stipules are small, the flower-stalk long, the sepals turned back and 

 the stigma lengthened — when the leaves are hairless we have canina 1 

 (Baker's lutetiana), when they are hairy, dumetorum. In the second 

 division the stipules are strong, the flower-stalk short, the sepals " sub- 

 persistent," i.e. they last longer on the fruit and are not so reflexed, 

 and the stigma is short and woolly. In this division we find a similar 

 sub-division : if the leaves are without hairs w^e get glauca, and if 

 hairy coriifolia.'^ 



These various sub-divisions are again divided into very numerous 

 varieties, the distinctions between them being based for the most part 

 on the greater or less woolliness of the stigma, the single or double 

 toothing of the leaves, and the presence in greater or less quantity, or 

 the absence of glands or of hairs on various parts, e.g. the flower stalk 

 or the underside of the leaf. Admitting the value of dividing Caninae 

 into the sub-sections and sub-divisions above mentioned, it remains a 

 question whether there is much to be gained by the extremely minute 

 division into varieties adopted by the author. Lindley refused to accept ■ 

 such characteristics as the presence or absence of pubescence or single 

 or double serratures in the leaves as being sufficient to establish specific 

 distinctions, and it is well known that Orepin towards the end of his 

 life declined to trouble himself with a too minute division of canina 

 forms. 



The highly interesting third part of Dr. Schwertschlager's book 

 goes some way to confirm the accuracy of this view^ For instance, in 

 considering the effect of external agents on Eoses he shows that great 

 quantities of moisture result in increasing the number of glands and 

 the serratures of the leaves of a rose. Thus a rose which in a dry 

 summer is found with few or no glands may in a wet one, such as 

 1872, be found glandiferous. It may not be at first obvious how wet 

 should affect the serratures of the teeth, but the explanation is this : i 

 while the primary teeth are generally glandless the secondary or tertiary 

 teeth are tipped with a gland, and so in increasing the serratures of 

 the teeth the plant obtains a greater number of glands. Hairiness, 



* In his treatment of English roses Major WooUey Dodd has adopted an 

 arrangement substantially similar to this save that he groups tomentella and 

 its allies as the first of five sub-groups of the Eucanitiae under the title of 

 11. Borreri. 



