Question: Fenestraria and Cyphostemma, are forms of what mutual items?

Context articles: Guttman scale
Data item
Japanese tea ceremony utensils
Cyphostemma
Hybrid LC Filter
Benefit society
Language convergence
Fenestraria
Item bank
Lexical item

In statistical surveys conducted by means of structured interviews or questionnaires, a subset of the survey items having binary (e.g., YES or NO) answers forms a Guttman scale (named after Louis Guttman) if they can be ranked in some order so that, for a rational respondent, the response pattern can be captured by a single index on that ordered scale.
 In other words, on a Guttman scale, items are arranged in an order so that an individual who agrees with a particular item also agrees with items of lower rank-order.
 For example, a series of items could be (1) "I am willing to be near ice cream"; (2) "I am willing to smell ice cream"; (3) "I am willing to eat ice cream"; and (4) "I love to eat ice cream".
 Agreement with any one item implies agreement with the lower-order items.
 This contrasts with topics studied using a Likert scale or a Thurstone scale.
A data item describes an atomic state of a particular object concerning a specific property at a certain time point.
 A collection of data items for the same object at the same time forms an object instance (or table row).
 Any type of complex information can be broken down to elementary data items (atomic state).
 Data items are identified by object (o), property (p) and time (t), while the value (v) is a function of o, p and t: v = F(o,p,t).
Equipment for tea ceremony is called "dōgu" (道具; lit., "tools"), or more specifically "chadōgu" (茶道具; "tea tools").
 "Chadōgu" can be divided into five major categories: "sōshoku dōgu" (装飾道具; "decorative items"); "temae dōgu" (点前道具; "items for the tea-making and service"); "kaiseki dōgu" (懐石道具; "items for the "chakaiseki" meal"); "mizuya dōgu" (水屋道具; "items used in the preparation room"); and "machiai dōgu / roji" "dōgu" (待合道具・露地道具; "items for the waiting room" / "items for the "roji" garden").
 A wide range of "dōgu" is necessary for even the most basic tea ceremony.
 Generally, items which guests prepare themselves with for attending a chanoyu gathering are not considered as "chadōgu"; rather, the term fundamentally applies to items involved to "host" a chanoyu gathering.
 This article, however, includes all forms of implements and paraphernalia involved in the practice of "chanoyu".
Cyphostemma is a flowering plant genus belonging to the family Vitaceae.
 These species are caudiciform and used to belong to the genus "Cissus".
 The genus name comes from Greek "kyphos", meaning "hump", and "stemma", meaning "garland".
Hybrid LC filter is a kind of electrical LC filter, which typically contains two conductive foil layers, separated by an insulation material and coiled on a core.
 Layers are typically made of copper or aluminum.
 One layer, which is placed between the voltage source, such as inverter, and a load, is called “the main foil”; this layer forms filter inductance.
 Another foil, called “the auxiliary foil”, is connected to a neutral potential (e.g. earth), forming the useful capacitance between foils.
 This way the self-capacitance of the main foil is crucially decreased.
 Filter is characterized by improved high-frequency performance (working frequency range is at least up to tens of MHz).
 The mutual inductance between foil layers is rather large, coupling factor is typically about 0.95-0.99.
 Higher the mutual inductance provided, better the damping properties of the hybrid LC filter.
A benefit society, fraternal benefit society or fraternal benefit order is a society, an organization or a voluntary association formed to provide mutual aid, benefit, for instance insurance for relief from sundry difficulties.
 Such organizations may be formally organized with charters and established customs, or may arise "ad hoc" to meet unique needs of a particular time and place.
 Many major financial institutions existing today, particularly some insurance companies, mutual savings banks, and credit unions, trace their origins back to benefit societies, as can many modern fraternal organizations and fraternal orders which are now viewed as being primarily social; the modern legal system essentially requires all such organizations of appreciable size to incorporate as one of these forms or another to continue to exist on an ongoing basis.
Language convergence is a type of linguistic change in which languages come to structurally resemble one another as a result of prolonged language contact and mutual interference.
 In contrast to other contact-induced language changes like creolization or the formation of mixed languages, convergence refers to a mutual process that results in changes in all the languages involved.
 Linguists use the term to describe changes in the linguistic patterns of the languages in contact rather than alterations of isolated lexical items.
Fenestraria (known as babies' toes or window plant) is a (possibly monotypic) genus of succulent plants in the family Aizoaceae, native to the Namaqualand in Namibia.
An item bank is a term for a repository of test items that belong to a testing program, as well as all information pertaining to those items.
 In most applications of testing and assessment, the items are of multiple choice format, but any format can be used.
 Items are pulled from the bank and assigned to test forms for publication either as a paper-and-pencil test or some form of e-assessment.
In lexicography, a lexical item (or lexical unit/ LU, lexical entry) is a single word, a part of a word, or a chain of words (= catena) that forms the basic elements of a language's lexicon (≈ vocabulary).
 Examples are "cat", "traffic light", "take care of", "by the way", and "it's raining cats and dogs".
 Lexical items can be generally understood to convey a single meaning, much as a lexeme, but are not limited to single words.
 Lexical items are like semes in that they are "natural units" translating between languages, or in learning a new language.
 In this last sense, it is sometimes said that language consists of grammaticalized lexis, and not lexicalized grammar.
 The entire store of lexical items in a language is called its lexis.