A480 Posted February 10, 2001 Is there a reliable way to differentiate between these sp? The cactus in question is not blue-ish, has nine radial spines(the central being the most prominent), six ribs and is only a little tacker (maybe half a foot tall). The spines are dark at the bottom, wood-coloured in the middle and darkening again towards the tip, maybe 2/3 of an inch long. It has some fairly prominent V-notches...it was sold as a tricho, so its probably not a stetsonia coryne...I pray. O yez, I brought a cactus recently and have no idea what this one is either. It has fuzzy orange areoles, five ribs(but was cut from a seven-ribbed plant), VERY short spines...here's where it gets wierd...it has numerous tiny spines on one side and on the other has between one and seven...it is a lot lighter shade of green than my Pedros' and the flesh looks *shiny* ie not at all like the leathery appearance that Tricho's usually have. It has notches, too, but they are more like slits than V-notches. My space cadet friend tried to make a tea with it, but unfortunately he was called back to Saturn while doing this and when he returned all the water had boiled off. He did however mention that the spoonful he sampled tasted Pedro-bitter...is this indicative of alkaloid content? It has already grown a new pup, so it's a fast-growing cat, whatever it is. I know this sorta shit is less than useless without a photo, but I was hoping some of the more educated amongst you could hazard a guess. Thanks in advance.... Share this post Link to post Share on other sites
Guest wira Posted February 10, 2001 Yeah, it's hard without a photo. The first one sounds like it could be some kind of peruvianus-type thing [remember peruvianus is not exactly a clearly-defined species, there are lots of different-looking things that get called peruvianus]. The second one, who knows - if I could see it I might hazard a guess, but otherwise I can't help. I should mention that I have seen pachanois that could definitely be described as being shiny, also ones that are light green. As I understand it, the bitterness is a good sign that alkaloids are present, though it can't indicate what alkaloids they are. Many cacti contain alkaloids. Macrogonus is also a poorly defined species which often gets mixed up with peruvianus, which is generally very similar. The dividing lines between them are not very clear but macrogonus having consistently darker spines overall is often used as a feature to distinguish it from peruvianus. I have a detailed description of knuthianus floating around but it needs translation. This one from Backeberg 1976 [Cactus Lexicon] is all I can offer for now, and you can see it isn't very detailed and probably is of little use in the real world... "T. knuthianus Backbg. Eventually tree-like, in age with a longer subterete trunk, to 3m high; branches to 10cm across, frosted, brilliant light bluish-green; ribs c. 7, rounded, to 3cm broad; radial spines 7; central spines 1, to 10cm long, it and the radial spines soon becoming concolorous whitish-grey although tipped yellowish at first; areoles large, with much felt; flowers large, white." Share this post Link to post Share on other sites
