PLANT TERMINOLOGY Plant terminology for the identification of plants is a necessary evil in order to be more exact, to cut down on lengthy descriptions, and of course to use the more professional texts. I have tried to keep the terminology in the database fairly simple but there is no choice in using many descriptive terms. The following slides deal with the most commonly used terms (more specialized terms are given in family descriptions where needed). Professional texts vary from fairly friendly to down-right difficult in their use of terminology. Do not be dismayed if a plant or plant part does not seem to fit any given term, or that some terms seem to be vague or have more than one definition – that’s life. In addition this subject has deep historical roots and plant terminology has evolved with the science although some authors have not. There are many texts that define and illustrate plant terminology – I use Plant Identification Terminology, An illustrated Glossary by Harris and Harris (see CREDITS) and others. Most plant books have at least some terms defined. To really begin to appreciate the diversity of plants, a good text on plant systematics or Classification is a necessity. PLANT TERMS - Typical Plant - Introduction [V. Max Brown] Plant Shoot System of Plant – stem, leaves and flowers. This is the photosynthetic part of the plant using CO2 (from the air) and light to produce food which is used by the plant and stored in the Root System. The shoot system is also the reproductive part of the plant forming flowers (highly modified leaves); however some plants also have forms of asexual reproduction The stem is composed of Nodes (points of origin for leaves and branches) and Internodes Root System of Plant – supports the plant, stores food and uptakes water and minerals used in the shoot System PLANT TERMS - Typical Perfect Flower [V. Max Brown] The Perfect Flower A Perfect (or Regular, or Bisexual, or Hermaphroditic or Polygamous) flower contains both Sepal male and female reproductive organs (this subject, and its exceptions, will be discussed in much more detail later). Petals The ideal flower is composed of 4 whorls of floral parts. The outer whorl is composed of Sepals, followed by a whorl of Petals, then Stamens and the Stamens (Male) innermost whorl is represented by the Pistils. All are modified leaves, the Stamens and Pistils are very highly modified for reproduction. Pistils (Female) Although a plant may seem simple, genetyic diversity and environmental factors produce an endless and dazzling variety of shapes and forms! Expect exceptions!! PLANT TERMS – Flowers [V. Max Brown] Petal (all petals = Corolla), usually white or colored to attract insects; absent in some plants Inflorescence – the flowering portion Pedicel - single flower stalk within the Sepal (all sepals = Calyx), usually of a plant (includes all flowers on the inflorescence. Peduncle – stalk of a solitary green and similar to leaves but may plant) flower or of whole inflorescence. The Pedicel be colored; absent in some plants, is the first Internode (stem between Nodes) but rarely Perianth – All Petals and Sepals below the flower; A Node is the position on a taken together, the Petals then stem where a branch and leaves may originate make up the inner whorl of the Perianth Anthesis – (time Tepals – term used for term) During the both petals and sepals time of flowering, when they are pollination, and/or generally alike and reproductive period difficult to tell apart PLANT TERMS – Flowers – Coalescence vs Adnation [V. Max Brown] Coalescence (Coalescent) and Adnation (Adnate) and synonyms are terms that describe fusion within the 4 major floral parts – petals, sepals, stamens, and pistils. Only the petals and sepals will be considered here. 1 -Coalescence (Coalescent) – the fusion of like parts such as one petal to another or all petals, etc. Connate is a synonym. Coherent is similar but means only superficially joined with like parts. 2 -Adnation (Adnate) – the fusion of unlike parts such as a stamens to a petals. Adnation is less common than Coalescence but does occur. Adherent is similar but means only superficially joined with unlike parts. In Describing sepals and petals the following prefixes are sometimes used (different authors will use some of the following). 1. (sym-) meaning fused such as sympetalous forming a corolla tube or syn- such as synsepalus forming a calyx tube, fusion may be little or a lot. Other synonyms are (gamo-) meaning fusion of like parts such as gamopetalus or gamosepalus. (Sym- and Syn- both mean united) 2. (a-) such as apetalous or asepalus meaning without petals or sepals (not present at all). 3. (chori-) such as choripetalous or chorisepalus meaning with separate or having distinct petals or sepals – however, some authors use the prefix chori- if any but not all petals for instance are fused. Other synonyms for separate petals (or sepals) is (poly-) as in polypetalous and (apo-) as in apopetalous. The term Free is sometimes used for separate unlike parts. The term Contiguous means touching but not joined in any way. PLANT TERMS – Flowers – petals and sepals [V. Max Brown] Polypetalous – petals separated or free, Sympetalous – all petals fused or united at least partially at base, Petaloid – Apetalous – without petals actually colored sepals in this case Polypetalous - (petals free, not fused) Apetalous - with 3 sepals Petaloids and Sepaloids - they (colored inside) and no petals appear to be petals and sepals but 4 blue sepals occur by a different origin (for (no petals) Sympetalous (lower petals fused) example a petal or bract may look like a sepal) Polysepalous – sepals separated or free, Synsepalous – all sepals fused or united at least partially at base, Asepalous – without sepals (rare) Some plants such as the Grass Family (Poaceae or Gramineae) lack both sepals and petals Polysepalous Synsepalous PLANT TERMS – Flowers – petals and sepals [V. Max Brown] Clawed – petals or sepals that are dramatically Hairy Petals narrowed at base Fringed Petals Reflexed petals Coneflower - with petals strongly Reflexed Reflexed sepals Reflexed – a floral part that is strongly bent back or down PLANT TERMS – Flowers – petal shapes and color [V. Max Brown] Notched (like a bite) or Toothed – if the notches or teeth are much less than half the length of the petal Color may be always true to a species or variations sometimes occur as above in Lobed – if the lobe is greater than a Cleft – greater these 2 species little but less then half the length of than half the length the petal of the petal The petal shape terms to the left are usually not rigorously enforced but the same terms will be used more formally in describing the leaves of trees such as Oaks Divided -almost as if Parted and then Parted – much the petals are totally greater than half the deeply lobed or cleft divided (to base) (5 to in this example length of the petal 10 above) PLANT TERMS – Flowers – bracts and phyllaries [V. Max Brown] Bract – a reduced leaf-like (specialized) structure sometimes found at the base of a flower or at the base of an Inflorescence – absence/presence, number, shape, etc. are often important ID aids. Involucre – a whorl of Bracts at the base of an Inflorescence, many families have Involucres) – some flowers may have only 1 bract or none. Bracts at base of individual flowers Spiny Bracts Phyllary – a Bract within an Involucre but above and below only in the Asteraceae Family (a very the Inflorescence large family) – often very important in the ID of plants in this family – more on phyllaries later Leaf-Like Bracts PLANT TERMS – Flowers – bracts and bracteoles [V. Max Brown] Involucel – 2nd order Involucre, a smaller set of bracts at base of a secondary inflorescence (secondary umbel in this case) – individual 2nd order bracts could be termed Bractlet(s) or Bracteole(s) Bract – at base of Inflorescence (part of an Involucre (several bracts subtending the inflorescence) PLANT TERMS – Flowers – Spathe and Spadix [V. Max Brown] Spathe – 1 or more bracts that partially encloses a flower or inflorescence; Spadix - a thickened spike of usually densely crowded small flowers (often protected by a Spathe) - found in a few families Spadix (no Spathe on this plant) Spathe (no Spadix) Spadix Spadix Spathe PLANT TERMS – Flowers – Asteraceae Family [V. Max Brown] The Asteraceae (Aster Family) have composite flowers (many flowers in one) set on a Receptacle (an expanded portion of the stem) on a peduncle. These flowers are composed of Ray and Disc florets (Floret - small flower or 1 of many small flowers). There are 3 types of composite flowers (see below). Disc Florets 2 types of Florets in Asteraceae Receptacle Ray florets – tubular at base, then a single flat ray or strap - ligulite Disc florets (tubular shaped, usually 4 or 5 lobed 3 types of flowers in the Family Asteraceae 1. Radiate – 2. Ligulate (strap- contains both ray shaped) – contains and disc florets only ray florets 3. Discoid – contains only disc florets PLANT TERMS – Phyllaries (Involucral Bracts in the Asteraceae) [V. Max Brown] In some Asteraceae (Aster Family), the shape and form of the Involucral Bracts (Phyllaries) are very important in ID – a few examples below and next slide. See section on Leaves for shape definitions linear to Spreading (pointing lanceolate, glandular outward), in long pointed triangular Filiform – thread- awl-shaped overlapping like (imbricated) rows oblanceolate to Fleshy with triangular lanceolate ovate, sharp point, black points very long Phyllaries