= Solution
The following definitions use current terminology in <plant morphology>; the examples illustrate the structures named in the historical paper.
\b[A <rhizome> is a persistent <plant stem>, usually growing horizontally at or beneath the ground surface.] Like other <plant stems>, a <rhizome> has <stem nodes> separated by <internodes>, with <buds> and often reduced, scale-like <leaves>. It can produce upward-growing <shoots> and <adventitious roots>. These features identify it as a <plant stem>, even though it is underground: a <root (botany)> does not bear <leaves> at <stem nodes>. The fleshy, branched part of <ginger> used as a spice is a <rhizome>, rather than a <root (botany)>.<Glossary of Botanical Terms by PlantNET>[Q–R, entries “rhizome” and “root”; I–L, entry “internode”]{ref}<Ginger by the Royal Botanic Gardens, Kew>[Plant description: branched underground stem and annual growth from it]{ref}
\b[A <spathe> is an enlarged, sheathing <bract> that encloses, at least initially, a <flower> or <inflorescence>.] A <bract> is a modified <leaf> associated with a <flower> or <inflorescence>. A familiar example is the pale green hood surrounding the <spadix> in <Arum maculatum>, or <cuckoo-pint>. The <spadix> is the thickened axis bearing the small <flowers>; the surrounding hood is the <spathe>. The <spathe> therefore belongs to the covering of the <inflorescence>, rather than being a large <petal> of one <flower>.<Glossary of Botanical Terms by PlantNET>[S, entries “spathe” and “spadix”]{ref}<Arum maculatum in Plants of the World Online>[CATE Araceae description: spathe tube, spathe limb and flower-bearing spadix]{ref}
\b[The <perianth> is the floral envelope: the <calyx> and <corolla> considered together, or whichever of these is present.] The <calyx> comprises the <sepals>, and the <corolla> comprises the <petals>. When the two sets look alike and are not differentiated into a recognizable <calyx> and <corolla>, their individual members are called <tepals>. A <lily> provides an example: its six conspicuous <tepals> form the <perianth>. The word is especially useful for such an undifferentiated envelope, but its collective meaning also includes a distinct <calyx> and <corolla>. The \x[stamens]{magic} and <carpels> are separate reproductive organs and are excluded from the <perianth>.<Glossary of Botanical Terms by PlantNET>[P, entry “perianth”; T–U, entry “tepal”]{ref}<Lilium in New South Wales Flora Online>[Generic description: six free tepals, followed separately by stamens and ovary]{ref}
\b[An <involucre> is a ring, or several rings, of <bracts> surrounding a <flower> or <inflorescence>.] In the <common daisy>, the small green <bracts> underneath and around the base of the <flower head> together form its <involucre>. That apparent single blossom is actually a <flower head> containing many small <flowers>, called <florets>. Its <involucre> surrounds this entire cluster; it is distinct from the <calyx> belonging to an individual <flower>.<Glossary of Botanical Terms by PlantNET>[I–L, entry “involucre”, flowering-plant sense]{ref}<Bellis perennis in New South Wales Flora Online>[Description: involucral bracts, white ray florets and yellow disc florets]{ref}
\b[A <sepal> is one of the parts making up the <calyx>, the outer floral envelope.] <Sepals> are commonly green and protect the other parts of a <flower> while it is in <bud>. They may remain separate or be joined into a <calyx> with free lobes or teeth. In a typical <buttercup>, the five outer <sepals> surround the inner, usually yellow <petals>. Thus one part is a <sepal>, the whole outer set is the <calyx>, and the <calyx> plus <corolla> is the <perianth>.<Glossary of Botanical Terms by PlantNET>[S, entries “sepal” and “segment”; C, entry “calyx”]{ref}<Ranunculus in New South Wales Flora Online>[Generic description: usually five sepals and five or more yellow or white petals]{ref}
\b[An <umbel> is an <inflorescence> in which the <flower> stalks arise together from one point at the top of a common stalk.] The stalk of each individual <flower> is a <pedicel>; the common supporting stalk is the <peduncle>. The <pedicels> spread out like umbrella ribs and are often of roughly equal length, producing a rounded or relatively level cluster. A flowering <onion> is an example of a simple <umbel>, with individual <flowers> at the ends of its <pedicels>. In a <compound umbel>, the primary branches instead end in smaller <umbels>, called <umbellets>, each carrying its own <flowers>. The defining feature is where the stalks join: a rounded outline alone does not establish that a cluster is an <umbel>.<Glossary of Botanical Terms by PlantNET>[T–U, entry “umbel”, figure 17 J; P, entries “pedicel” and “peduncle”]{ref}<Allium in New South Wales Flora Online>[Generic description: umbellate inflorescence; cultivated examples include onion, Allium cepa]{ref}<Glossary of the Flora of Newfoundland and Labrador>[Entries “ray” and “umbellet”; figure 14, compound umbel]{ref}
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