Pea shoots are the leaves of the pea plant which are bright green and succulent, with accompanying tendrils that curl up and have a subtle sugary flavor that is delicious raw. It is from a snow pea plnt variet that is cultivated specifically for its shoots. Like peas, pea shoots have a sweet crispness that goes beautifully with just about anything and a pleasant sweet pea flavor. These are an extravagance and are seasonal, arriving in markets in early spring.
Lotus Root (actually a rhizome) is usually sold in buff colored sausagelike links, typically sold in 2's or 3's. Sometimes it's sold cleaned and sometimes it's sold still covered in mud. ..and is fairly ugly ..until it is cut open to reveal it's paper snowflake-like pattern inside. The flavor and crisp texture is smething like jicama but slightly more astringent.
Ong Choy, also called Water Spinach is sold in tall leafy bundles with long flat arrow shaped leaves and thin hollow stems. You can split the pale green leaves lenthwise and soak them in water which makes them curl into little corkscrews for decoration. Buy young tender leaves and stems.
Mizuna is found in most baby green mixes and is also found mature in Japanese grocery stores where it is sold in a clump, much like frisee. Look for dark green leaves.
Tatsoi is often found in Spring mix or Mesclun mix. This brassica grows in a rosette, sometimes flat against the ground and has crinkled dark green leaves and often a white stem much like that of Bok Choy, to whom it is related.
Choy Sum aka Yau Choy, or Yow Choy Sum or other similar variations, also sometimes just called Chinese greens, although there are so many of them, it can get confusing. This one has broad oval green leaves with little yellow flowers and pale green stems, no bigger than your pinkie. They are slightly mustardy in flavor, only slightly ..and much milder. They are tender and sweet, kind of like a cross between spinach and broccoli. This is one of the most popular vegetables in China.