Robert, I know very little about the different species though I've been under the impression Poplar and Basswood are different species altogether. When I looked up Basswood I found it's also called Lime (not related to the fruit) but found no connection with Poplar...here's what I found:
The timber of lime trees is soft, easily worked, and has very little grain, and a density of 560kg per cubic meter[2]. It is a popular wood for model building and intricate carving. Especially in Germany, it was the classic wood for sculpture from the Middle Ages onwards, and is the material for the elaborate altarpieces of Veit Stoss, Tilman Riemenschneider and many others. Ease of working and good acoustic properties also make it popular for electric guitar and bass bodies and wind instruments such as recorders. In the past, it was typically used (along with Agathis) for less-expensive models. However, due to its better resonance at mid and high frequency, and better sustain than alder, it is now more commonly in use with the "superstrat" type of guitar. It can also be used for the neck because of its excellent material integrity when bent and ability to produce consistent tone without any dead spots according to Parker Guitars. In the percussion industry, basswood is sometimes used as a material for drum shells, both to enhance their sound and their aesthetics. It is also the wood of choice for the window-blinds and shutters industries. Real wood blinds are often made from this lightweight but strong and stable wood which is well suited to natural and stained finishes.
It is known in the trade as basswood, particularly in North America. This name originates from the inner fibrous bark of the tree, known as bast (Old English language). A very strong fibre was obtained from this, by peeling off the bark and soaking in water for a month; after which the inner fibres can be easily separated. Bast obtained from the inside of the bark of the lime tree has been used by the Ainu people of Japan to weave their traditional clothing, the attus.
