Hort Botany Quiz #4 Stem Anatomy and Morp Flashcards

Terms Definitions
that part of the seedling plant that extends from the cotyledonary node to the primary root
any axis of a plant which develops from a bud, possesses nodes and internodes, and its capable of bearing leaves and buds at nodes
Functions of Stem
Conducts water and nutrients from roots to leaves, storage, asexual reproduction (in some) and protection
Woody plant that will reach 12' ht
Several main woody stems, 12' <
Must be supported in order to grow vertically, with long trailing stem
plant with a very short stem, this is almost hidden by leaves overall effect is similiar to looking down on a rose flower; herbaceous
Acaulescent plant
one that appears to be stemless; these often have stems that grow horizontally or underground
point of leaf attachment, often slightly swollen
stem between nodes. Length varies with species and environment
apical buds, bud at tip of stem. Gives rise to parts of the shoot system: more stem, leaves, reproductive organs and auxillary buds
Leaf primordia

Bud primordia
meristematic cells that will make a leaf and bud primordia;
is a layer of cells that covers the apical meristem, leaf and bud primordia
lateral bud - bud found in the angle formed by a leaf and a stem. The angle is called the leaf axil
Buds on herbaceous plant, some woody tropical plant, and a few woody temperate-zone plats are often naked; or not covered by bud scales


1 scale form

2 or three that don't overlap

serveral scales overlap like shingles
Bud scale color


Some shade of brown, tinged w/ r & g

Clustered vs singly

Rounded, oblong, fusiform, ovoid, acuminate

pressed against the stem

sticking out of the stem (aux. buds only)
Bud scale scars
are left on the stem when the bud falls; the part of the stem between 2 successive areas of bud scale scars represents one year's growth
Leaf scars
are left when leaves fall; Uaf scars vary in size, shape, pattern on the stem (phyllotaxy) and in size, number, arrangement of vascular bundle scars within. These remnants are of vascular tissue, which connected the stem to a leaf


modified slender pointed twig usually bears minute leaf scars and buds; honeylocust and hawthorn

modified stipules or other leaf parts; black locust and barberry

pointed superficial twig tissuesl since they have no vascular connections, they are easily removed; rose


excavated; no pith; parenchyma cells have disintedgrated

Divided into empty horizontal chambers

pith is solid but has partitions of firmer, often darker tissue

Spongy; pith is solid but soft

Firm; pith is solid and hard


Starshaped as in Oaks

triangular, with rounded corners as in alders

Round, lots of it as in Lilacs
Woody Stem components
Shoot (1 yr or less; bares leaves)
Twig (1 yr or less; dropped leaves)
Branch - stem wich is more than 1 yr
Arm - main stem of a woody plant
Stem which has a relatively large pith or hollow space in center usually arising from the ground, in an arching habit; often removed after 2 to 3 yrs due to sharply reduced flower production

Woody stem with very short internodes, usually for bearing heavy fruits

Main stem of a woody plant
Stem tendril
very slender, coiling item that is sensitive to contact; found at nodes in leaf axils, used for support of weak stems (also herbaceous)
Herbaceous Stem components
Succulent stem - one which is large and fleshy, storing large amounts of H2O, often green and able to photosythesize; xerophytic (survive by this means)
Green, leaflike stem. All but one genus of cacti have cladodes


horizontal perennial tough stem usually less than 2" dia borne underground at least partially, adventitious roots

usually slender horizontal stem that creeps along the ground, rooting at its nodes and often forming new plants there

stolon with very long internodes

Enlarged terminal portion of a slender-underground stem

short, vertical underground stem which has fleshy leaves called bulb scales, at least one terminal bud, and one aux. bud (for bulblet)
short, flat, thick vertical underground stem, producing cormels from auxillary buds
is the region in dicots between the vascular cambium and the epidermis; while in monocots it is the region in which the vascular bundles are scattered; Dicots have some collenchyma in this region as well
Pith rays
consist of parenchyma cells located from the pith between the vascular bundles to the cortex of dicots
Monocot bundles (ID)
Monkey face, with 3 large vessel elements (eyes and nose) and the lacuna, the air space formed by breakdown of a vessel element (mouth)
Dicots and gynosperm
woody and produce a secondary as well as primary tissue, in both the roots and stems. The secondary body originates from mitotic divisions of two lateral meristems, the vascular cambium and the cork cambium
vascular cambium
is derived from relatively undifferentiated cells located between the primary x and ph and from the pith ray, parenchyma cells between the vascular bundles. Vascular cambium forms a secondary xylem (annual ring) to the inside and secondary phloem to the outside

is conducting xylem

is nonconducting xylem. darker and denser due to tanin, resins, oils and gums.
Cork cambium
differentiates within the primary phloem. It produces cork to the outside and cork parenchyma to the inside. 1) annual additons of xylem force all other tissues outward 2) the epidermis, cortex, and primary phloem slough off so new tissue must be made to protect the inner, living tissue
periderm + phloem
cork + cork parenchyma
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