Tabernaemontana is a genus of flowering plants in the family Apocynaceae.
 It has a pan-tropical distribution, found in Asia, Africa, Australia, North America, South America, and a wide assortment of oceanic islands.
 These plants are shrubs and small trees growing to 1–15 m tall.
 The leaves are evergreen, opposite, 3–25 cm long, with milky sap; hence it is one of the diverse plant genera commonly called "milkwood".
 The flowers are fragrant, white, 1–5 cm in diameter.
Stenostachys is a genus of plants in the grass family, found only in New Zealand.
 It is sometimes included in the genus "Elymus".
Chaffing and winnowing is a cryptographic technique to achieve confidentiality without using encryption when sending data over an insecure channel.
 The name is derived from agriculture: after grain has been harvested and threshed, it remains mixed together with inedible fibrous chaff.
 The chaff and grain are then separated by winnowing, and the chaff is discarded.
 The technique was conceived by Ron Rivest and published in an on-line article on 18 March 1998.
 Although it bears similarities to both traditional encryption and steganography, it cannot be classified under either category.
Elymus californicus is a species of wild rye known by the common name California bottlebrush grass.
 This grass is endemic to California where it is an uncommon species known from a few counties in the San Francisco Bay Area.
 It grows between one and two meters in height.
 The tall, erect stem is nearly naked, bearing the occasional sheathing leaf with a blade 10 to 20 centimeters long.
 It bears an erect inflorescence which curves as it becomes heavier in grain.
 Each inflorescence is divided into three or four nodes with three or four spikelets per node.
 Each spikelet is between one and two centimeters long, not counting a long awn about two centimeters long.
Krupnik (Polish), Krupnik (Belarusian) or Krupnikas (Lithuanian), is a traditional sweet alcoholic drink similar to a liqueur, based on grain spirit (usually vodka) and honey, popular in Poland, Belarus and Lithuania.
 In Poland it is grouped in the nalewka category of alcoholic beverages.
 Mass-produced versions of krupnik consist of 40–50% (80–100 proof) alcohol, but traditional versions will use 80–100% grain alcohol as the base.
 Honey, in particular clover honey, is the main ingredient used to add sweetness, as well as up to 50 different herbs.
 There are many versions and some recipes have been passed down through generations.
 Krupnik originated in the territories of present-day Belarus, which were at the time part of the larger Polish-Lithuanian Commonwealth.
 Krupnik is sometimes heated before being served.
A perennial grain is a grain crop that lives and remains productive for two or more years.
 While many fruit, nut and forage crops are long-lived perennial plants, all major grain crops presently used in large-scale agriculture are annuals or short-lived perennials grown as annuals.
 Scientists from several nations have argued that perennial versions of today's grain crops could be developed and that these perennial grains could make grain agriculture more sustainable.
Elymus is a genus of perennial plants with approximately 150 species in the grass family, related to rye, wheat, and other widely grown cereal grains.
Grains are small, hard, dry seeds, with or without attached hulls or fruit layers, harvested for human or animal consumption.
 "Grain crops" are grain seed producing plants.
 The two main types of commercial grain crops are cereals (wheat, rye) and legumes (beans, soybeans).
Threshing is a key part of agriculture that involves removing the seeds or grain from plants (for example rice or wheat) from the plant stalk.
 In the case of small farms, threshing is done by beating or crushing the grain by hand or foot, and requires a large amount of hard physical labour.
 A simple thresher with a crank can be used to make this work much easier for the farmer.
 In most cases it takes two people to work these: one person to turn the crank and the other to feed the grain through the machine.
 These threshers can be built using simple materials and can improve the efficiency of grain threshing.
 They can also be built with pedals, or be attached to a bicycle, so that the person operating it can simply pedal to reduce the work even more and make threshing faster.
Abacarus hystrix (cereal rust mite or grain rust mite) belongs to the family Eriophyidae.
 They are extremely small with adults measuring up to one millimeter in length and only have four legs at the front of the body.
 Viewing by the human eye requires, a 10 – 20X lens.
 The adult mites are usually yellow but also have been seen to be white or orange.
 The cereal rust mite was first found on Elymus repens (couch grass), a very common perennial grass species.
 It has now been found on more than 60 grass species including oats, barley, wheat and ryegrass, found in Europe, North America, South Africa and Australia.
 Mites migrate primarily through wind movement and are usually found on the highest basal sections of the top two leaf blades.
 "Abacarus hystrix" produces up to twenty overlapping generations per year in South Australian perennial pastures, indicating that the species breeds quite rapidly.
 It has been noted that the cereal rust mite can cause losses in yield of up to 30-70%.

Question: Which is category of grain plants, Tabernaemontana or Elymus?
Answer: Elymus