Although there is an assocaition with the Tulip (Tulpanglas) series because of Landberg's use of the drawn stem flaring out to the wide foot, you are quite right to observe that those pieces are cased, whereas your candlesticks are not. That is the link that first made me feel that these candlesticks were indeed by Nils Landberg when I first saw them years ago. Like you though I could not pin them down as I could find no illustration.
Nowadays we have the Internet. It's wonderful to use when the information that's available is correct :shock: , but if someone else describes it as, say, WMF, why should you question it? Well you have. Possibly like me you thought that they had resemblance to the Tulip glass series, which is why you put the question in the first place.
Answer to your question? Orresfors "Gabriel" candlesticks code number 1724/11 NL, height 190mm. Also avalilable in sizes 230 and 270 - codes 1724/12 and 1724/13 respectively. Originally self-coloured transparent glass (various colours), but laterly only in clear.
Trust those instincts Cathy