Written by Acorn Sales Company, manufacturing stamps and seals since 1964 · Reviewed by Holly R, VP of Sales and Marketing at Acorn Sales, against the Missouri Board for Architects, Professional Engineers, Professional Land Surveyors, Professional Landscape Architects, and Licensed Interior Designers and § 327.411.1 and.4, RSMo (current version effective August 28, 2026) on 21 September 2026 · Updated 21 September 2026
The prefix is PLA, and the lower arc reads PROFESSIONAL LANDSCAPE ARCHITECT. 20 CSR 2030-3.060(1) prints one design for four professions and swaps two things. Both are exact: PL is not the Missouri prefix, Registered Landscape Architect is not the Missouri legend, and the number is never shown bare. The rule requires “two concentric circles between which appear in roman capital letters, the words, ‘State of Missouri’ on the upper part of the seal” and the profession on the lower part, with the name and prefixed number inside the inner circle.
The circle is fixed at one and three-quarters inches with no tolerance and no separate inner dimension, which creates the layout problem. Landscape architects have three long words on the lower arc where an architect has one, on the same 1-3/4 inch die. That is a proofing step before the die is cut, not a reason to enlarge it.
The seal is heavier here than in most states. Section 327.411.2, RSMo, makes it “the legal equivalent of the licensee’s signature whenever and wherever used” and fixes responsibility for the landscape architectural documents on the owner of the seal. Interns and in-training individuals get no seal.
Missouri landscape architect seal requirements at a glance
| Requirement | Missouri rule | Source |
|---|---|---|
| Seal required | Yes | § 327.411.1 and.4, RSMo (current version effective August 28, 2026) |
| Required elements | Two concentric circles, State of Missouri, Professional Landscape Architect, Your name as licensed and Your license number prefixed PLA | 20 CSR 2030-3.060(1) |
| Size and shape | One and three-quarters inches (1-3/4 inches) in diameter. 20 CSR 2030-3.060(1) requires the licensee to “secure a seal one and three-quarters inches (1 3/4″) in diameter of the following design”. | 20 CSR 2030-3.060(1) |
| Device allowed | 20 CSR 2030-3.060 permits “an embossing seal, a rubber stamp, or a computer-generated image, identical in size, design and content with the provisions of section (1) above.” An inked rubber stamp is the safe. | 20 CSR 2030-3.060 |
| Signature and date | The rule requires the licensee to “affix his/her signature and place the date when the document was originally sealed, at the minimum”. | 20 CSR 2030-3.060(3) |
| What must be sealed | All final technical submissions, including drawings, specifications, plats, surveys, exhibits, reports and certifications of construction under section 327.411.1, RSMo. | § 327.411.1,.3,.4, RSMo |
| Electronic seal | No named technology and no named standard. | 20 CSR 2030-3.060(3) |
| Renewal and lapse | Not addressed. Neither section 327.411, RSMo, nor 20 CSR 2030-3 states what happens to the seal on lapse, revocation or surrender, and neither requires it to be destroyed or returned. Checked the current text of section. | § 327.411, RSMo, and 20 CSR 2030-3 (silent) |
| Firm requirements | The firm needs a certificate of authority, but not a seal and not a number on the sheet. | 20 CSR 2030-10.010 |
| Regulator | The Missouri Board for Architects, Professional Engineers, Professional Land Surveyors, Professional Landscape Architects, and Licensed Interior Designers | Sections 327.011 and 327.411, RSMo, Chapter 327 (current versions effective August 28, 2026, L. 2026 S.B. 1233) |
Is a seal required in Missouri?
Section 327.411.1, RSMo, provides that each professional landscape architect “shall have a personal seal in a form prescribed by the board, and he or she shall affix the seal to all final technical submissions”, with technical submissions defined to include “drawings, specifications, plats, surveys, exhibits, reports, and certifications of construction”. Section 327.411.2 makes the seal “the legal equivalent of the licensee’s signature whenever and wherever used” and fixes responsibility for the landscape architectural documents on the owner of the seal. The design comes from 20 CSR 2030-3.060, and section 327.411.4 excuses preliminary or incomplete documents from sealing.
What must appear on the seal
- Two concentric circles
- State of Missouri
- Professional Landscape Architect
- Your name as licensed
- Your license number prefixed PLA
Nothing is optional. 20 CSR 2030-3.060(1) requires “two concentric circles between which appear in roman capital letters, the words, ‘State of Missouri’ on the upper part of the seal and either ‘Architect,’ or ‘Professional Engineer,’ or ‘Professional Land Surveyor’ or ‘Professional Landscape Architect,’ as the case may be, on the lower part, and within the inner circle the name of the licensee, together with his/her license number preceded by the roman capital letter(s) A for Architect, PE for Professional Engineer, PLS for Professional Land Surveyor or PLA for Professional Landscape Architect.” So the lower arc reads Professional Landscape Architect and the number is preceded by PLA. Watch the two easy confusions: PLA is not PL, and Professional Landscape Architect is not Registered Landscape Architect. Interns and in-training individuals get no seal. No expiration date and no board emblem belong on the face.
Size and shape
One and three-quarters inches (1-3/4 inches) in diameter. 20 CSR 2030-3.060(1) requires the licensee to “secure a seal one and three-quarters inches (1 3/4″) in diameter of the following design”. A single figure, no tolerance, and no separate dimension for the inner circle. The longest legend in the Missouri set has to be laid out inside the same circle the architects use.
Embosser, rubber stamp or digital
20 CSR 2030-3.060 permits “an embossing seal, a rubber stamp, or a computer-generated image, identical in size, design and content with the provisions of section (1) above.” An inked rubber stamp is the safe buy, and it is the better choice here because the ring carries three long words that an embossed impression tends to lose.
Signing and dating
The rule requires the licensee to “affix his/her signature and place the date when the document was originally sealed, at the minimum”. Printed documents take “a handwritten ‘wet signature’ identification containing the name of the person who applied it”; native electronic documents take “a digital signature with an electronic authentication process attached to or logically associated with the document”; and for PDF and similar formats “a scanned signature is acceptable if it is an accurate depiction of the licensee’s actual signature”. The date is the original sealing date. Signing across the seal is not addressed in the rule or in section 327.411, RSMo.
PLA, not PL, and the longest legend in the state on the same 1-3/4 inch circle
Missouri prints one design for four professions and swaps two things. 20 CSR 2030-3.060(1) sets the lower arc to Professional Landscape Architect and the number prefix to PLA. Both are exact. PL is not the Missouri prefix, Registered Landscape Architect is not the Missouri legend, and the number is never shown bare.
The layout problem follows from the arithmetic. The circle is fixed at 1-3/4 inches for everyone, and landscape architects have three words to fit on the lower arc where an architect has one. That is a proofing step, not a reason to enlarge the die, because the rule states a single diameter with no tolerance.
One Missouri provision is worth knowing if your sheets travel inside somebody else’s set. Section 327.411.3, RSMo, lets a licensee attach a statement over signature and seal “specifying the particular technical submissions, or portions thereof, intended to be authenticated by the seal, and disclaiming any responsibility for all other technical submissions”. Given that section 327.411.2 makes the seal the legal equivalent of your signature, that disclaimer is the cleanest way to limit what your PLA seal is taken to cover.
Which documents must be sealed
All final technical submissions, including drawings, specifications, plats, surveys, exhibits, reports and certifications of construction under section 327.411.1, RSMo. The rule allows one sealing point on bound work, letting the licensee “sign, seal, and date the title page, an index page, or a seals page on bound multiple page documents” where the signed page identifies the pages it covers. Preliminary or incomplete work is excused by section 327.411.4 but must carry the legend “The information on this document is preliminary or incomplete, not for construction, recording purposes, or implementation” in an obvious, easily readable location. Sealing technical submissions not prepared by the licensee or under the licensee’s immediate personal supervision is prohibited. Section 327.411.3 allows an optional statement, over signature and seal, identifying which submissions the seal authenticates and disclaiming the rest, which is useful where a landscape architect’s sheets sit inside a larger architectural set.
Electronic and digital seals
No named technology and no named standard. The digital signature must be “unique to, and under the sole control of the person using it; it must also be capable of verification and be linked to a document in such manner that the digital signature is invalidated if any data on the document is altered”. A scanned signature is enough for PDF delivery, while a true digital signature is required for a document delivered in its native electronic format.
Renewal, lapse and retirement
Not addressed. Neither section 327.411, RSMo, nor 20 CSR 2030-3 states what happens to the seal on lapse, revocation or surrender, and neither requires it to be destroyed or returned. Checked the current text of section 327.411, a scan of Chapter 327 for the word seal, and the whole of 20 CSR 2030-3. Nothing found says the license number changes on reinstatement.
Firm requirements
The firm needs a certificate of authority, but not a seal and not a number on the sheet. A corporation rendering landscape architectural services in Missouri applies for a certificate of authority under 20 CSR 2030-10.010. Neither that chapter nor 20 CSR 2030-3.060 requires the certificate number or a corporate seal to appear on technical submissions.
What to check before you order
Order a 1-3/4 inch die with two concentric circles and roman capitals. STATE OF MISSOURI on the upper arc, PROFESSIONAL LANDSCAPE ARCHITECT on the lower arc, and inside the inner circle your name as licensed with your license number preceded by PLA. Proof the lower arc before the die is cut, since three long words on a 1-3/4 inch circle is where these go wrong. Take the inked rubber stamp as the working device. No expiration date, no emblem, no discipline line. No proof of licensure is required at the counter and nothing is filed with the board.
Browse landscape architect stamps and seals.
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Frequently asked questions
Is a seal required for landscape architects in Missouri?
Yes. Section 327.411.1, RSMo, provides that each professional landscape architect “shall have a personal seal in a form prescribed by the board, and he or she shall affix the seal to all final technical submissions,” with technical submissions defined to include “drawings, specifications, plats, surveys, exhibits, reports, and certifications of construction.” The design comes from 20 CSR 2030-3.060. The current statutory version is effective August 28, 2026.
What has to appear on a Missouri landscape architect seal?
Two concentric circles, State of Missouri on the upper arc in roman capitals, Professional Landscape Architect on the lower arc, and inside the inner circle your name as licensed together with your license number preceded by the roman capitals PLA. No expiration date and no board emblem belong on the face.
What size is a Missouri landscape architect seal?
One and three-quarters inches in diameter. 20 CSR 2030-3.060(1) requires the licensee to “secure a seal one and three-quarters inches (1 3/4″) in diameter of the following design.” A single figure, no tolerance, and no separate dimension for the inner circle, so the longest legend in the Missouri set has to be laid out inside the same circle the architects use.
Embosser, stamp or computer image in Missouri?
All three. 20 CSR 2030-3.060 permits “an embossing seal, a rubber stamp, or a computer-generated image, identical in size, design and content with the provisions of section (1) above.” An inked rubber stamp is the practical buy, and the better choice here because the ring carries three long words that an embossed impression tends to lose.
What signature does Missouri require?
The rule requires the licensee to “affix his/her signature and place the date when the document was originally sealed, at the minimum.” Printed documents take “a handwritten ‘wet signature’ identification containing the name of the person who applied it”; native electronic documents take “a digital signature with an electronic authentication process attached to or logically associated with the document”; and for PDF and similar formats “a scanned signature is acceptable if it is an accurate depiction of the licensee’s actual signature.” The date is the original sealing date. Signing across the seal is not addressed.
Which Missouri documents have to be sealed?
All final technical submissions, including drawings, specifications, plats, surveys, exhibits, reports and certifications of construction, under section 327.411.1, RSMo. The rule allows one sealing point on bound work, letting the licensee “sign, seal, and date the title page, an index page, or a seals page on bound multiple page documents” where the signed page identifies the pages it covers. Sealing technical submissions not prepared by you or under your immediate personal supervision is prohibited.
What about preliminary work in Missouri?
Section 327.411.4 excuses preliminary or incomplete work from sealing, but it has to carry the legend “The information on this document is preliminary or incomplete, not for construction, recording purposes, or implementation” in an obvious, easily readable location.
Can I limit what my Missouri seal covers?
Yes, and it is worth doing when your sheets travel inside somebody else’s set. Section 327.411.3, RSMo, lets a licensee attach a statement over signature and seal “specifying the particular technical submissions, or portions thereof, intended to be authenticated by the seal, and disclaiming any responsibility for all other technical submissions.” Given that section 327.411.2 makes the seal the legal equivalent of your signature, that disclaimer is the cleanest way to bound what your PLA seal is taken to cover.
What is the Missouri digital signature standard?
No named technology and no named standard. The digital signature must be “unique to, and under the sole control of the person using it; it must also be capable of verification and be linked to a document in such manner that the digital signature is invalidated if any data on the document is altered.” A scanned signature is enough for PDF delivery, while a true digital signature is required for a document delivered in its native electronic format.
Does a Missouri landscape architecture firm need a seal?
The firm needs a certificate of authority, but not a seal and not a number on the sheet. A corporation rendering landscape architectural services in Missouri applies for a certificate of authority under 20 CSR 2030-10.010, and neither that chapter nor 20 CSR 2030-3.060 requires the certificate number or a corporate seal to appear on technical submissions. Nothing about lapse, revocation or surrender of the device is stated in section 327.411, RSMo, or 20 CSR 2030-3.
