Paphiopedilum helenae
I remember seeing photos of and reading about this species back in the late 90s or early 2000s not long after it was discovered. Although the flowers weren't necessarily to my taste, I was intrigued by how small this species was purported to be. If it's not the smallest known species of Paphiopedilum, it's pretty close and would only have been dethroned of that title by some of the more recent discoveries.
I've had this tiny Paph for several years now, purchased when it was a single growth plant listed as near blooming size. Now it's a small bush of at least 12 growths. I grow it on what I understand to be the warm side of its preferences, these guys are said to enjoy cool nights and a distinct wet-dry season. So, blooming it might take a little work, but it seems to be a pretty easy grower.
I set it on a windowsill this winter to give it a very cool exposure (i.e. near freezing, had ice on the inside once or twice due to this year's exceptionally cold spells), but that actually happened after I noticed what I assumed was flower a sheath initiating. I just figured if they prefer cool and dry conditions this time of year to help initiate spikes, it'd be less likely to abort the spike if I gave it what it wants.
I love how small this plant is. Although I'm growing it inside 2 stacked clay pots to help provide some evaporative cooling, the plant itself is in a 2.5" (7ish cm) plastic pot. The largest growth has a leaf span of only 6 inches (15cm) and even with the flower spike, the plant is less than 4 inches (10cm) tall.
Paph. helenae is starting to become an important species for breeding compact growing Paphiopedium hybrids, which is very good news for us indoor growers that use artificial lights and grow shelves for our plants. Smaller plants means more room for more plants!
There's quite a bit of bright yellow in the flower, which I really love. I also like the white margin on the dorsal and that proportionally oversized staminode.