CMG GardenNotes #173 Identifying Broadleaf Flowering Trees and Shrubs

Transcription

1 CMG GardenNtes #173 Identifying Bradleaf Flwering Trees and Shrubs Outline: I. Leaf characteristics, page 2 a. Leaf arrangement, page 2 b. Leaf frm, page 2 c. Leaf venatin, page 2 d. Leaf shape, page 3-4 e. Leaf surface texture, page 4 II. Stem characteristics, page 5 a. External stem features, page 5 b. Axillary bud type, page 5 c. Stem surface texture, page 6 d. Internal stem features, page 6 III. Fruit characteristics, page 6 a. Key f fruit types, page 7 IV. Identificatin Keys t Landscape Trees, page 8 Identificatin f bradleaf trees and shrubs is a skill mastered with practice and knwledge f the plant families. Mst trees and shrubs can be readily identified t family and genus with a basic knwledge f the plant s characteristics and the use f a key. There are always a few exceptins with plants that d nt lk like their relatives. Identificatin t specific epithet requires mre skill and a clser lk at plant characteristics. Identificatin t variety and cultivar can be very difficult, as the defining characteristics may nt be clearly bservable frm plant samples. Identify the plant t the level yu are cmfrtable and t what the task requires! Keys can be arranged in a variety f ways, but mst start by separating Gymnsperms frm Angisperms (the key t the cmmn Cnifers was cvered in GardenNtes #172), then start with brad, easily identifiable characteristics t narrw the plant t family level. Usually, the mre specific and smaller plant characteristics will be used t narrw the plant dwn t genus and specific epithet. The fllwing sectins will cver the mst cmmn characteristics yu will encunter in a plant key. Sme f these characteristics yu will cme acrss with every plant yu key, and yu shuld be cmfrtable using these terms. Nte: This shuld be a general review frm the Btany trek, but the infrmatin is vital t the plant ID prcess

2 I. Leaf Characteristics a. Leaf Arrangement (see Figure 1) Alternate Arranged in staggered fashin alng stem (i.e. Willw) Oppsite Pair f leaves arranged acrss frm each ther n stem (i.e. Maple) Whrled Arranged in a ring arund the stem (i.e. Catalpa) Figure 1: Leaf arrangement n the stem b. Leaf Frm (see Figure 2) Simple Leaf blade is ne cntinuus unit (i.e. Cherry, Maple, and Elm) Cmpund Several leaflets arranged n ne petile Pinnately cmpund Leaflets arranged n bth sides f a rachis an extensin f the petile, like a feather (i.e. Hneylcust). Palmately cmpund Leaflets radiate frm ne central pint at the tip f the petile (i.e. Ohi Buckeye and Hrse Chestnut). Dubly pinnately (r bipinnately) cmpund leaflets are arranged n a branches ff f the rachis (i.e. Kentucky Cffee Tree). Figure 2: Variety f leaf frms Nte: Smetimes identifying a "leaf" r "leaflet" can be cnfusing. Lk at the petile attachment. A leaf petile attaches t the stem at a bud nde. There is n bud nde where leaflets attach t the petile. c. Leaf Venatin (see Figure 3) Pinnately veined leaves have a central vein dwn the center with smaller veins branching ff and extending t the leaf margin (i.e. Elm, Peach, and Linden). Palmately veined leaves radiate smaller veins ut in a fan-shaped pattern frm a central pint at the petile leaf stem (i.e. Maple, Mulberry, and Pplar). Figure 3: Variety f leaf venatin 173-2

3 d. Leaf Shape (see Figures 4-7) Leaf shape is a primary tl in plant identificatin. Descriptins ften g int fine detail abut general leaf shape, and the shape f the leaf apex and base. There is n hard and fast dividing line where ne type suddenly becmes anther type; rather it is a judgment call. When using keys, lk at several leaves frm the plant, select the average shape, and be flexible in yur descriptin. The authrs f thes plant identificatin keys are aware f the variatin within plants, and will ften write several ptins int the key. The fllwing figures shw the cmmn verall shapes, leaf apexes and bases, and leaf margins: Figure 4: Variety f verall leaf shapes Figure 5: Variety f Leaf Apex shapes 173-3

4 Figure 6: Variety f leaf base shapes Figure 7: Variety f leaf margins e. Leaf Surface Texture Lk at all the leaf surfaces, abve and belw. Nte the lcatin, clr, density and length f scales and hairs. These terms are cmmnly encuntered when describing leaf surface texture Ciliate Orderly, widely spaces hairs alng the edge (margin), als called fringed Glandular Hairs bearing glands Glutinus Sticky t the tuch Scabrus Hairs very shrt Stellate Star shaped hair (needs magnificatin) Velutinus Dense hairs f equal height, like velvet 173-4

5 II. Stem Characteristics Stems cntain several features imprtant t identifying plants. Cut int the stem t see the pith. Lk at the epidermis, buds, arrangement f the ndes and any surface cating r texture. Fr winter identificatin f wdy plants, lk at the pattern f the scales n the terminal and lateral buds and the shape f the leaf scars. a. External Stem Features (see Figure 8) Terminal bud This bud is where grwth that lengthens the stem happens. The yung, dividing cells are prtected by Terminal Bud Terminal bud scales Axillary Bud Axillary bud These buds, when actively dividing, will becme a new branch. They are smaller versins f the terminal Lenticels bud and can als be prtected by scales Leaf scar The mark left n stem where leaf was Leaf Scar attached. The shape f the leaf scar is ften used in wdy plant identificatin. Bundle scar Marks left in the leaf scar frm the vascular tissue attachment. The shape f the bundle scare is ften used in wdy plant identificatin. Lenticels Wdy twigs have these pres in the bark t allw fr gas exchange. These lk like little dts alng the stem. Bundle scars Figure 8: External Stem Features b. Axillary Bud Type The type f axillary bud (the way the scales are arranged ver the bud) is anther feature used in plant identificatin. Figure 9 illustrates bud types used in the Manual f Wdy Landscape Plants. (See Figure 9) Figure 9: Axillary Bud types 173-5

6 c. Stem Surface Texture The surface f wdy twigs may have a texture that can be used t distinguish ne plant frm anther. Terms used t describe the surfaces f stems can als apply t leaves. Farinse Cvered with a mealy, pwdery substance Glabrus Smth Glaucus Having a blm r whitish cvering, ften waxy Hirsute Cvered with carse, stiff hairs, rugh enugh t break the skin Pubescent Cvered with hairs Scurfy Cvered with small scales Tmentse Cvered with shrt, matted r tangled, sft, wly hairs d. Internal Stem Features Pith is the tissue fund at the center f stems and rts. Pith characteristics may prvide identificatin clues. A diagnal cut acrss the stem reveals if the center f the stem is hllw r if the pith is slid r chambered. A straight cut acrss the stem reveals the shape f the pith (runded, star r triangle). (See Figure 10). Figure 10: Internal stem features used in plant identificatin III. Fruit Characteristics Generally, the identificatin f trees and shrubs is dne withut fruit, as the fruit is nly arund fr a shrt seasn. Hwever, when fruit is present, it can be a tl in plant identificatin. Fr example, legumes are characteristic f the Pea family (Fabaceae). The fllwing is an utline key defining the different fruit types yu may see n trees and shrubs. A nte n flral terms here: the pistil refers t the female part f a flwer. A pistil can have ne vary (chamber) r several varies fused tgether. Single flwers can als have multiple pistils. The pistil is the part f the flwer that the fruit is derived frm, s these differences in fruit types cme frm differences in the arrangement f the pistil. A gd place t practice yur fruit identificatin is at the grcery stre! 173-6

7 a. Key f Fruit Types 1. Simple fruit fruit frmed frm ne pistil A. Dry fruit 1) Dehiscent fruits these fruits split pen when mature t release seeds a) Capsule Many seeded fruits frmed frm mre than ne united carpels. b) Fllicle Cmpsed f ne carpel but splits pen at maturity alng ne suture expsing seeds. c) Legume (Pd) Cmpsed f ne carpel that splits pen alng tw sutures (like a pea pd). Characteristics f mst members f the Fabaceae family. 2) Indehiscent fruits these fruits d nt split pen when mature; the seed stays intact inside a) Achene One seeded fruit with seed attached at nly ne place t the pericarp. Pericarp is very clse-fitted and des nt split pen, at least alng regular established lines. b) Samara One r tw seeded with a membranus wing. c) Nut A bny, hard, ne-seeded fruit. d) Nutlet A tiny nut. B. Fleshy fruits 1. Berry The entire fruit is fleshy. 2. Drupe the fruit is clearly differentiated int three layers; the utside layer is the epidermis, the middle layer is fleshy, and the inside layer frms a stny pit arund the seed. 3) Pme The pericarp is surrunded by the flral cup (hypanthium),which becmes the fleshy edible part f the fruit

8 2. Aggregate fruits Develp frm a single flwer that cntains many separate pistils. The fruits frm the individual pistils are arranged n ne receptacle. Examples: Fragaria (strawberry) aggregate f achenes Liridendrn (Tuliptree) aggregate f samaras Maclura (Osage-range) aggregate f drupes Magnlia (Magnlia) aggregate f fllicles Rubus (Raspberry) aggregate f drupes 3. Multiple fruits Cnsists f several flwers which are mre r less united int ne mass. Example: Mrus (Mulberry), Pineapples IV. Identificatin Keys t Landscape Trees The fllwing is a helpful list f plant identificatin keys yu can use in yur bradleaf shrubs and trees identificatin: Key t Cmmn Landscape Trees and Shrubs f Clrad, CMG GardenNtes #177 at Flra f Clrad Jennifer Ackerfield. Brit Press Trees and Shrubs f Clrad. Jack L. Carter. Secnd editin, 2006 Authrs: David Whiting, Linda McMulkin, Janne Jnes, Alisn O Cnnr, Laurel Ptts, and Christine Prins, CSU Extensin. Line drawings by Sctt Jhnsn and David Whiting; used by permissin. Clrad Master Gardener GardenNtes are available nline at Clrad Master Gardener training is made pssible, in part, by a grant frm the Clrad Garden Shw, Inc. Clrad State University, U.S. Department f Agriculture and Clrad cunties cperating. Extensin prgrams are available t all withut discriminatin. N endrsement f prducts mentined is intended nr is criticism implied f prducts nt mentined. Cpyright Clrad State University Extensin. All Rights Reserved. CMG GardenNtes may be reprduced, withut change r additins, fr nnprfit educatinal use. Revised Octber