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Plant morphology (植物形態)
Terms for morphology (形態用語)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

[shoot (stem), flower, seed, leaf , root, hair]
[species, plant taxonomy, growth, cell, Latin and Greek]

Brief history
1672 Grew, 1675 Malpighi: anatomy
1790 Gothe: Metamorphase der Pflanzen (植物変態論) → metamorphose → morphology
1817 Goethe (JW von Goethe, literary figure): Zür Morphologie → firstly used the term morphology
1827 de Condolle: Organographie (器官学)
1868 Sachs, 1877 de Barg: Plant Anatomy: developmental morphology (or anatomy)

flower ____ sexual cell
mature plant _ fertilized
young plant → embryo → embryology

Basic techniques

Flower ()

Flower = reproductive organ for seed plants → producing seeds

Angiospermae → flower (s.s.)
Gymnospermae → cone (球果) (= flower, s.l.)

1912 Potonie, 1914 Lignier, 1916 Bower, 1917 Kidston & Lang: The most simple organization of vascular plant = furcate

1930 Zimmermann: proposed Telome theory based on Rhynia (middle of Devon, small teresstrial fern discovered from Scotland

→ telome = gymnosporangia on the apex → adhesion → seed coat or testa (hypothesis)

1948 Lam, 1960-63 Melville, 1966 Meeuse: proposed a hypothesis on flower structure based on Telome theory → new morphology

1961 Eames: A determinate stem tip bearing sporophylls and, commonly, other appendages that are sterile

1980 Bold: It is the reproductive organ of seed plants. The top of spur shoot becomes remarkably short, and it forms the receptacle. The flower is regarded as specialized shoot with the specialized organ of floral leaf

Position of flower on stem

terminal flower (頂生花), e.g., tulip
axillary flower (腋花), e.g., mint, Kummerowia striata (Thunb.) Schindl.

Perianth (花被)

= perigonium, perigon or perigone
the sterile parts of a flower = sepals + petals (花弁) or tepals (花被片)

Sepal (萼片): one of the modified leaves comprising a calyx
Calyx (萼): usually green outer whorl of a flower consisting of separate or fused sepals

Tepal (花被片)
outer tepal (外花被片)
innter tepal (内花被片)
Chasmogamous and cleistogamous flower (開放花と閉鎖花)
Chasmogamous flower or chasmogamic flower (開放花): open petals encircling exposed reproductive parts, usually we see this ordinary flower
Cleistogamous flower or cleistogamic flower (閉鎖花): not open petals but are self-pollinated - reproducing during a period less favorable for the usual blossoms or chasmogamous flowers

Ex. Viola spp. (e.g., Viola verecunda), Impatiens noli-tangere, Chloranthus serratus

Stamen (雄蕊)

pollen-producing organ on a flower = anther + filament
Androphore: a column formed from the fusion of multiple filaments
anther (): the part of a flower that contains pollen

a introrse  b latrorse  c extrorse

References of terms for expressing directions
bear (pp. borne): 位置する
ascending 上向き ↔ descending 下向き
extrorse 外向き ↔ introrse 内向きの

introrse: facing or turned inwards or towards an axis - promoting self pollination
extrorse: releasing their pollen to the outside of the flower
latrorse (側向): dehiscing laterally, neither toward nor away from the center of the flower

antrorse 前向き (adv. -ly) ↔ retrorse 逆向き(後ろ向き)
filament (花糸): the stalk of a stamen, bearing the anther at its apex
anther locule (葯室) = microsporangium, connective (葯隔)

Nectary (蜜腺)

Secretory apparatus of nectar - internal floral nectary = most of them on the base of flowers
Stamen origin
No vascular bundle

Corydalis: only one, not develping two anthers
Phalanx: 2 types = one species of syngensious + attached filament
⇔ extrafloral nectary = nectary not originating from flowers

Nectar tube (蜜腺管): Ex. Pelargonium

Pollen (花粉)

a fine to coarse powdery substance, produced by the male part of a flower, comprising pollen grains
Pollen grain (花粉粒)
each pollen grain contains vegetative cells (a single cell in most species) and a reproductive cell

microspore → division → pollen grain

Dispersal unit:
pollen grain
Size: < between 10μm and > 200 μm

Wind pollinated, airborne pollen grains normally range from 10 μm to 80 μm

Shape (aspect ratio): determined by ratio between the length of the polar axis and the equatorial diameter
Structure (aperture):
pollen grain

mono-, di-, tri-, tetra-, penta-, hexa-, poly- (> 6) + porate, colporate, coporoidate

Pistil (雌蕊)

A discrete organ in the center of a flower capable of receiving pollen and producing a fruit
= ovary (子房) + style (花柱) + stigma (柱頭)
ovule (胚珠): a part inside the ovary that contains the female sex cell and develops into a seed

Placenta (胎座)

an organ formed by the sustained apposition or fusion of fetal membranes and parental tissue for physiological exchange
Placentation (胎座配列)
1) Parietal (and marginal) placentation (側膜胎座)
2) Axial placentation (axially or axile) (中軸胎座)
3) Free-central (and basal) placentation (特立中央胎座)
Fig. 7.5. Heterostyly in Lythrum salicaria. Diagrams of the three forms of flowers, in their natural position, with petals and calyx removed on the near side. The dotted lines with the arrows show the directions in which pollen must be carried to each stigma to ensure full fertility (Darwin 1877).

Corolla (花冠)

corolla (花冠): all of petals on a flower

Petal (花弁): modified leaves surrounding the reproductive organs
petal (petalous 花弁がある, petaloid 花弁状の)

corona or paracorolla (副花冠) corona: an additional structure between the petals and the stamens of a flower, often looking like petals
Symmetry (相称性, 対称性)
↔ asymmetry (非相称性), adj. asymmetric ↔ symmetric)
1. radial symmetry (放射相称, 放射整正)

symmetrical plane ≥ 2 → actinomorphic flower (放射相称花)
Ex. lily, tulip

2. bilateral symmetry, zygomorphy or zygomophic symmetry (左右相称)

symmetrical plane = 1 → stereoscopic

a. median zygomorphy (中央左右相称)
b. transversal zygomorphy (横断相称)
c. oblique zygomorphy (斜面相称)

flower: near - front ⇔ far - back / leaf: near - up ⇔ far - down
adaxial side (向軸側): surface facing the axis (head in leaf)
abaxial side (背軸側): surface facing away from the axis (tail in leaf)
basipetal (求基的): developing apex downward towards the base

Corolla Flower
Terms for corolla morphology: rotate, cup-shaped, funnel-shaped (infundibuliform) (Ipomoea nil), campanulate (Enkianthus campanulatus), urceolate, calceolate, labiate (cf. bilabiate), personate, cruciate, hypocrateiform (Clerodendrum trichotomum), liliaceous, rosaceous, galeate, caryophylleous, irregular

Floral diagram (花式図)

Floral formula (花式)

A method of recording floral structure, in particular, configuration of floral organs, expressed by a series of symbols, letters, and numbers


Ca (or K), calyx or whorl of sepals
Co (or C), corolla or whorl of petals
CaCo, perianth, if sepals and petals are alike
A, androecium, or whorl of stamens
G, gynoecium (pistil), or ovary bearing carpels

n,number of organs

Ca3, three sepals
Cam-n, sepals ranging from m to n
Ca, numerous sepals

FD: fully distinct or fused
FD: fully fused or connate, especially for the carpels of the gynoecium
╰╯: basally fused or connate
╭╮: apically fused or connate
♂: male unisexual flower
♀: female unisexual flower
⚥: hermaphrodite bisexual flowers
*: staminode; a sterile stamen
G___: ovary inferior to insertion point of the other whorls. The floral whorls are epigynous to the gynoecium
G: ovary superior to insertion point of other floral whorls. The floral whorls are hypogenous to the gynoecium
G___: ovary inferior to superior, with variations

Floral diagram (花式図)

A stylized representation of flower structure in which the whorls of floral parts are shown as a series of concentric circles. All floral segments arising at the same level are placed, in their correct relative positions, in the same circle. When appropriate, fusion of parts is also indicated. The ovary is represented in cross section in the center of the whorls.
Campanula Floral diagram shown by Campanula medium. Black dashed line shows the cross-section. 1: position of the main axis, 2: cross-section through the lateral flower; 3: bracteole; 4: subtending bract.

●: floral axis or rachis

Magnolia stellata

Lamium album var. bartatum


Oxalis corniculata L. [Oxalidaceae]
Kerria japonica (L.) DC. [Rosaceae]
Solanum nigrum L. [Solanaceae]
Robinia pseudoacacia L. [Fabaceae]
Leucanthemum vulgare [Asteraceae]
  • Grisebach R. 1854. Grundriss der systematischen Botanik fur akademische Vorlesungen. Verlag der Dieterichschen Buchhandlung, Gottingen: Dietrich

Inflorescence (花序)

A. Indeterminate inflorescences (無限花序)
flowering from base to top
Spike (穂状花序)
an elongate, unbranched inflorescence with sessile flowers
Raceme (総状花序)
an elongate, unbranched inflorescence with pedicelled flowers
Corymb (散房花序)
a flat-topped raceme with elongate pedicels reaching the same level
Umbel (傘形花序)
a flat-topped or rounded inflorescence with the pedicels originating from a common point (determinate or indeterminate)
Panicle (円錐花序)
a branched raceme
Fig. Indeterminate inflorescences
B. Determinate inflorescences (有限花序)
flowering from top or middle
Uniflowered inflorescence (単頂花序)
Dichasium (二出集散花序)
Monochasium (単出集散花序)
Rhipidium or fan-shaped cyme (扇形花序): not catergorized when rhipidium is merged with scorpioid cyme
Scorpioid cyme (or cincinnus) (蠍形花序): a zig-zag cyme with branches developing alternately on opposite sides of the rachis
Drepanium (鎌形花序)
Helicoid cyme (or bostryx) (蝸形花序): a cyme in which the branches develop only on 1 side

helicoid cyme__scorpioid cyme

Pleicohasium (多出集散花序)
Glomerule (団散花序)
Hypanthium (隠頭花序)
Cincinnus 扇状集散花序(多出集散花序)
Fig. Determinate inflorescences
C. Specific inflorescences
inflorescence Spadix (肉穂花序), including indefinite inflorescence: (small) flowers borne on a fleshy stem, e.g., Araceae (サトイモ科)
Catkin (ament, 尾状花序): cylindrical flower cluster (a spike), with inconspicuous or no petals
Cyathium (杯状花序): a cup-shaped involucre enclosing an apetalous, pistillate flower surrounded by several staminate flowers, only Euphorbia

[inner structure of leaf]

Leaf ()

An organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology

= blade + petiole + stipule
Basic function = photosynthesis

leaf shape
Fig. Morphology of a typical leaf

Bract () or bract leaf (苞葉)

a leaf growing from the area just below a flower and sometimes different in shape and/or color from the main leaves

adj. bracteate, bracteal) ⇔ ebracteate, bractless: not forming bracts

Involucre (総苞)
bracts appearing in a whorl subtending an inflorescence

adj. involucrate, involucral

Involucral bract or scale (総苞片): one or more of the bracts surrounding the capitulum and forming the involucre
Bracteole (小包葉): a secondary bract subtending a flower within an inflorescence

Leaf shape (葉形)

Dimorphism (二型性)
Dimorphic leaf (二型葉)

Fertile and infertile leaves:
Pteris mutilata
Thelypteris palustris (somehow)

Leaf margin

Leaf margin (葉縁)

1 entire, 2 undulate, corrugated, 3 repand, 4 crenate, 5 serrate, 6 serrulate, 7 dentate, 8 denticulate, 9 ciliate, 10 fimbriate, 11 double serrate, 12 incised (Makino 1977)
Leaf base

Leaf base (葉基部)

1: attenuate (adj. cuspidate, pointed, acutish, blunt), 2: cuneate, 3: truncate (sub-), 4: obcordate (heart-shaped), 5: auriculate, 6: sagittate, 7: hastate (spear-shaped)* (*: used not only leaf shpae but also other organs)
1: petiolate. 2: sheathing. 3: sessile. 4: amplexicaular. 5: perfoliate. 6: decurrent. 7: connate-perifoliate. 8: pelate, shield-shaped

Stipule and leaflet (托葉・小葉)

One of a pair of lateral appendages, often leaflike, at the base of a leaf petiole in many plants

stipule stipule
Salix rorida_______________ Chaenomeles speciosa

Pseudostipule (仮托葉): an often modified basal pair of leaflets of a compound leaf appearing very close to the stem, e.g., Artemisia indica

Petiole (leaf stalk, 葉柄)

= the stalk that attaches the leaf blade to the stem
petiole Maekawa hypothesis (1969)

F: foliage leaf = F class leaf
S: scale leaf = S class leaf
Phylogenetical origins are different between F and S classes

Phyllode hypothesis (Kapler 1973)



Vein, or nervure (葉脈)

One of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other expanded plant organ

nunmber of veins (NV, 中軸分岐数)

  • Sato T, Tsuyuzaki S. 1988. Quantitative comparison of foliage development among Dryopteris monticola, D. tokyoensis and a putative hybrid, D. kominatoensis, in northern Japan. Botanical Magazine, Tokyo 101: 267-280
  • Tsuyuzaki S. 2000. Characteristics of "number of veins" to estimate leaf maturity in Pteris mutilata (Pteridaceae). Journal of Plant Research 113: 415-418
    Abstract: In this report, the author suggests that the number of veins (NV) is useful to estimate leaf maturation for a tropical fern Pteris mutilata, as has been established in ferns of cool temperate regions. NV expressed developmental stages better than any other leaf size parameters, such as blade length, blade width, stipe length, and total length (blade+stipe length). The leaf shape became more oblong and/or slender after the plant matured, which could be measured by two shape parameters, (blade width)/(total length) and (blade width)/(blade length). Principal component analysis using all the morphological parameters showed that NV is categorized into size parameters, although NV has been considered to differ somehow from the other size parameters. Thus NV represents one of the size parameters that is the most appropriate to estimate leaf maturation.
  • Tsuyuzaki S, Taguiam CG. 2007. Ecosystems and agro-forestry systems in Luzon Island, Philippines P. Activity report: IGBP-MESCC/TEMA
Fig. 1. Schematic representation of the leaf development
of Dryopteris saxifraga. Number indicates the number of
veins on each leaf. Arrows with number indicate the
counting method of number of veins. FL, a fertile leaf with
sporangia. (Sato 1985)

Shape index (形状指数)

Several indeces have been proposed to quantitatively express leaf shapes Aspect ratio (horizontal to vertical ratio) = L/W

L: leaf length
W: leaf width

Dissection index = l/(2√(Sπ))

l: leaf marginal length
S: leaf area

Patton's diversity index = l/(2πS)

Collective form of leaf blade (葉身の集合形)

1. Simple leaf (単葉)

adj. unifoliate

2. Compound leaf (複葉)

Leaflet (foliole, lobule) (小葉) (adj. lobulated 分葉状の, 葉が分かれた)
Petiolule: a leaflet stalk (adj. petiolulate)
compound leaf
Imparipinnate (奇数羽状), odd-pinnate: pinnate with a single leaflet at the apex
Paripinnate (偶数羽状), even-pinnate: pinnate with a pair of leaflets at the apex
Bipinnate (二回羽状), doubly pinnate: pinnate and having leaflets that are themselves pinnate
Tripinnate (三回羽状): having bipinnate leaflets arranged on each side of a rhachis
Ternate (三出)
Biternate (二回三出): having ternate leaves, each division of which is itself ternate
Runcinate (逆向き羽状): having a lacerated aspect with the projection pointing away from the apex, like dandelion leaves
Lyrate (頭大羽状): having a large terminal lobe and smaller rounded lobes toward its base
Pectinate (櫛状): resembling a comb

[ anatomy | measurement | root generation ]

Root ()

Belowground system ≈ Root system

Three types of root systems

Rhizoshpere: areas that are directly influenced by root activities

Tree: secondary growth (auxetic growth)

Dicotyledons (and gymnosperms): main root (taproot, 主根/直根) + fine root 細根 (+ rootlet 支根)

Fine root < φ 3-5 mm

Monocotyledons: fibrous root

+ adventitious root (不定根): arising from an organ other than the root

numerous on underground stems, such as rhizomes, corms and tubers - somtimes conducting vegetative propagation

The roles of roots
  1. Nutrient and water transportation

    The role of roots on decomposition

    Secreting carbohydrates (exudates) to soil → bacteria / carbon sink
    Absorbing nutrients from soil → changing the environments not only for plants

  2. Supporting system
    → Role of roots in the stability and protection of slopes
Root1 Root2
[1] Dicotyledons (Glehnia littoralis). [2] Monocotyledons (Elymus mollis). At a seacoast in Hakodate City on September 24 2009.
→ Root system of Carex kobomugi
Plant roots. A: taproot, B: fibrous root (髭根), C: adventitious root, D: adventitious roots of cuts (cut on left, cut with roots after a few weeks on right).


Aerial root (気根): above-ground roots in the air

breathing, e.g., mangrove trees
support, e.g., ivy
Prop root (支柱気根): a shoot-borne nodal root formed at a stem node above the ground, and growing directly into the soil

Storage root (貯蔵根)

≈ tuberous root, e.g., sweet potato, cassava and dahlia

Pneumatophore = respiratory or knee roots (通気根): usually partially exposed roots of a wetland plant, such as mangrove, that function in the intake of oxygen from the atmosphere

(adj = hairy)

Hair ()


Trichome (トリコーム)

Fine outgrowths or appendages on plants, e.g., hair, glandular hair, scale, and papilla.
Papilla, pl. -ae (乳頭突起): the mere outgrowths of the epidermal cells that increasing the surface → protecting the stem against herbivores, relating to drought resistance
Glandular hairs (腺毛): epidermal secretory structures
Salt and chalk glands: typical structures of salt resistant plants
Nectaries: present usually on entomophilous species, produce a sugary solution to attract the insects
Gland ()
functionally as a plant structure which secretes one or more products
oil spot (油点)

pale gland (明点)
dark gland (黒点)

Hair on leaf and stem

[Adjectives used for taxonomical description]
  • patent hair (開出毛): hair growing at right angles