As indicated in the topic title, this topic touches on a very technical subject, and thus is of little value to anyone who is not a botanist or horticulturalist. (I have no intention of figuring out plant families for planar flora-- we're talking about vegetation with an entirely different evolutionary history and ecology)
TORILIAN
Barausk: Books say it resembles beech, and that the wood eventually becomes tough as iron. I will have to do some research on all the plants known as ironwood and see if a suitable one stands out.
Beetle Palm: Bit of a no brainer that it's in Arecaceae (the palm family).
Blueleaf: The books state that this tree closely resembles a maple, so presumably it belongs to that genus or a similar one, placing it in Sapindaceae (soapwort) family.
Chime Oak: The description indicates that this plant belongs to the genus Quercus (oak), placing it in Fagaceae (the beech family)
Felsul: Far too little information is given to make any determination on what family it belongs to, but if I had to wager a guess, I'd say Fabaceae (the legume family)
Flame Heather: Clearly this belongs in the Ericaceae (heath) family. Because Calluna (true heather) doesn't actually grow in the arctic, this is most likely a species of Cassiope or Phyllodoce.
Laspar: I believe this belongs to Cupressaceae (the cypress/cedar family)
Mule Plant: The description of the flowers as "daisy-like" is a dead giveaway that it's a composite (Asteraceae).
Roseneedle Pine: Unfortunately, its description (flowers emerging from leaftips) does not fit any real life plant family that I know of. However, it comes closest to Lamiaceae (nettle/mint family), as it bears a close resemblance to rosemary, which can become a woody shrub about 3 and a half to four feet high in favorable conditions. Because it is a flowering plant, it cannot possibly be a conifer.
Sealberry: There are only three berry-producing plant families capable of growing in the arctic-- Ericaceae, Rosaceae, and Caprifoliaceae. Only a single genus of Rosaceae is capable of living in the arctic-- Rubus[/i ] (the bramble, whose fruits do not match the description of sealberry), while only a single species in Caprifoliaceae-- [i]Lonicera caerulea (the honeyberry).
However, many species of berry producing plants in Ericaceae (heath family) live in or near the arctic, including crowberry (Empetrum nigrum), cranberry (Oxycoccus oxycoccus), and blueberries/huckleberries. Thus, it is safe to assume that sealberry is in the family Ericaceae.
Silverbark: Its habitat and description closely resemble Betulaceae (the birch family), and in fact there are some species-- or at least some cultivars-- which only reach about 20 feet in height *though I don't know of any that come anywhere close to a maximum trunk width of 4 inches*
Sleepweed: Since it's described as having a milkweed-like pod, it's likely in Apocynaceae (the dogbane family)
Suthwood: This bizarre tree doesn't sound like anything from real life (zigzag pattern sound rather Darwintastic if you ask me), but its preference for subtropical habitats combined with its habit of intertwining with other specimens of its species to create a hedge reminds me of strangler figs-- some of which do indeed create impenetrable hedges (and the hedges can even consist of different species of strangler fig!)
Vundwood: Though the growth habit does not match, the other qualities of this tree closely match Lauraceae (laurel family), particularly the cinnamon scent and preference for Mediterranean climate.
Weirwood: This also appears to be a species of oak (Quercus), placing it in Fagaceae.
OERDIAN FLORA
Deklo: The description sounds very close to Lombardy Poplar, so it's probably in Betulaceae (birch family), if not a species of Populus itself.
Kara: Though hardly the only family with "irritating resin", Anacardiaceae (the cashew/sumac family) certainly fits. (The cashew family also includes the familiar fruit known as mango)
Roanwood: Obviously this belongs somewhere in Cupressaceae (cypress/cedar family), probably either subfamilia Sequoioideae since the books specifically refer to it as being like a "sequoia" rather than "like a redwood".
Sablewood: The books only state that this is a conifer with black wood when oiled, meaning it's a Pinopsid.
Uskwood: Says the leaves look like a maple, which in and of itself does not narrow the possibilities down very much. However, the mention of luscious fruit combined with the leaf description makes it very likely a member of Sapindaceae (soapwort family), even though none of the real-life species produce fruit anywhere near the size of grapefruits.
Yarpick: Many trees in Malvaceae (mallow family), particularly tribus Bombacoideae, produce thorns on their trunk, including Ceiba (Kapok). Most of them produce dry capsular seed pods, but there are members within the tribe which produce large fruits (though Yarpick is described as having a small fruit)
I love the geekiness that went into this, I'll definitely use it to stump my players, if you'll pardon the pun.