Ligules and Stipules Oh My !

Design and InstallationGarden Caregarden TriviaPlant Health CareUncategorized
Written By Peter Morris

Ligule

 

The word ligule comes from Latin "ligula" which means strap. It is a thin outgrowth at the junction of a leaf and leafstalk.  Ligules occur only in some grass species.  Basically, it acts in a passive way in protecting the culm and leaves that it encloses.  It protects the leaf from the entry of water, dust and harmful spores. The ligule is the continuation of the leaf sheath and it encircles or clasps the stem as does the sheath.

 

Ligules take several forms.  From a translucent membrane to a fringe of hairs. They can be very short 1–2 mm to very long 10–20 mm.  Some have smooth edges, others ragged.  A few species of grasses don't even have a ligule!

The three basic types are: membranous, a fringe of hairs (ciliate), and absent. The shape, length, and appearance of the ligule is used to categorize and separate genera and species.

  

Stipule

 These are outgrowths borne on either side of the base of a leafstalk (petiole). A pair of them are considered part of the anatomy of the leaf of a typical flowering plant (Angiosperm).  In many species, the stipules are inconspicuous or entirely absent.  These of course are termed exstipulate !!! 

Stipules are basically a modified leaf.  Not very common in the recently evolved monocotyledons.  They usually occur in pairs in the dicots.

 

They function to protect the emerging leaf or bud.  Usually short-lived -  they drop off after the leaves matures.

Very common in the Beech family – Stipules protect the emerging bud and leaves.

 

Stipules are morphologically variable and might appear as glands, scales, hairs, spines, or laminar (leaf-like) structures. If a single stipule goes all the way around the stem, it is known as an ochrea.

 

Ochrea

 

Types of stipules

 

Duration

The three types of stipules according to duration are caducous, deciduous and persistent. Caducous stipules fall off before the leaf unfolds.  Deciduous stipules fall off immediately after the leaf unfolds. Persistent stipules remain attached to the plant. 

Interpetiolar

Ficus (common houseplant – rubber plant) are distinguished by terminal conical stipules that cover the newly developing leaves. It gets shed as the new leaf expands. Called "interpetiolar"  - it is located in between the petioles, as opposed to being attached to the petioles.  Generally these stipules are fused together, so it appears that there's just one between each leaf instead of two.  

Just Plain Scary !

Sometimes the stipules evolve for protection – check out these scary stipules!

 

Euphorbia

 

Common locust tree – Robinia

 

For grasses with ligules or beeches with stipules -

Call Plant Specialists TODAY !

Don't delay – the sooner the better !

    

GREENING NEW YORK FOR OVER 51 YEARS !

 Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBAAll photographs used with permission @SHUTTERSTOCK

Peter Morris

Peter was born and raised on a beautiful green island in the midst of a tropical rainforest. He was introduced into the world of plants at the age of six when his grandmother, an avid Spanish gardener herself, asked him to help her grow seeds for her pepper garden. He was hooked! By the time he was a teen, he had his own rose and orchid collection numbering in the hundreds. Botany was in his blood, and that is what he set out to study.

His passion brought him to NY in the late seventies to further his education. His tenacity allowed him to work full time at Plant Specialists while he completed a MS in Plant Biology. As a manager at the time he felt unsatisfied with his knowledge of business and business processes. Peter felt compelled to learn, so he then pursued and completed an MBA in Quality Management within a few short years.

Peter’s other passion is teaching. His natural ability is quickly consumed by our staff in all subjects in Botany, Horticulture, and Landscaping. He created an immense reference library of more than 3,500 plants providing an invaluable resource for our staff.

Peter’s breadth of knowledge and wisdom allows him to effectively diagnose the needs of plants. Sometimes just by walking into a garden he can create a prescription that fixes even the hardest issue. He is our Staff Botanist, Diagnostician, and all around Mentor. Recently, he has put his immense knowledge and skills into developing a new department that focuses on Plant Healthcare. As he puts it, “Magic through Science”. The PHC staff that surround him have avidly consumed his teachings. Substantially developing their own plant wisdom, many have taken on difficult plant health issues with spectacular results.

Plant Healthcare has been an instant success with customers! The proper treatment of insects and diseases including Organic methods has made pest control a necessity for every plant. Correcting hormonal imbalances caused by planting in containers or refurbishing soils leached of nutrients by irrigation systems are big challenges PHC has become quite comfortable addressing. The scientific approach to the complex demands of keeping plants healthy in our harsh city environment has made many a customer say WOW!

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