I might be being unduly unfair but I was dissatisfied with this puzzle overall. On the plus side the idea was neat and simple and many of the clues were good and relatively easy. But enumerations were wrong in a couple of places, at least according to Chambers which was recommended for the theme words and so I would have though was the reference for the clue answers. One entry was a not a word and a couple of other clues were just unsatisfactory.
The biggest failing though was that I couldn’t identify a unique solution. As far as I can tell one of the sets of words is not unique and with the other set it is arguable that it may not be unique. Of course there may be some resolving feature that I have missed (such as a missing part of the preamble as happened with the online version of EV853) and so I stand ready to apologise. The theme sets, highlighted in red and blue, took the form of three letter seed words which then grew by the addition of letters and anagramming. In one set both PEA -> PALE -> SEPAL and SEA -> SALE -> SEPAL fitted the grid. In the other set I think ROE -> GORE is the right answer but GOE -> GORE also fits depending on how the extra letter is considered to be added before being anagrammed.
(XY Z)* anagram
X[Y]Z insertion
X[y]Z deletion
ZYX< reversal
X…Z extremes
vwXYZab hidden word
| Across | |||
|---|---|---|---|
| ESCALLOP | (SCALPEL+O)* | ||
| PEA or SEA | |||
| 6 | SCIPIO | S[CI[p]PI]O | a cippus is a monumental pillar | 
| 7 | HERALD | HERA+LD | |
| 9 | ALAN | bALANce | |
| 10 | GIROLLE | I+ROLL in G…E | |
| PLACES | (SEPAL+C)* | ||
| 12 | APT | abbr | |
| 13 | DUNDEE | DUN+DEE | though Dundee is a city not a town. | 
| 14 | LEASOW | LEA+SOW | |
| 17 | PREWAR | P[REW]AR | in Chambers the term is hyphenated rather than one word. Also I’m not convinced by the definition here. 1588 is the year of the defeat of the Spanish armada but surely that was just part of the Anglo-Spanish War (1585–1604)? I realise that a war from Spenser’s time is needed for the surface reading but I think the resulting clue is weak. | 
| 19 | SLAP UP | SLAP+UP | in Chambers the term is hyphenated rather than two words. | 
| 20 | VEDIST | VE[DI]ST | |
| 22 | AGNATE | A+GNAT+E | Ehrenberg collected and studied plants and animals, insects were a specialism. | 
| 26 | USE | dd | |
| 27 | ROAD UP | (A PROUD)* | |
| 28 | SNOOPER | (O+PERSON)* | definition is private eye | 
| 29 | ULVA | efUL VArie | |
| 30 | ARRIET | ARR[I]ET | this is not a word. Using the dropped aitch in word play is okay but surely ‘Arriet isn’t reasonable as the defined answer? | 
| ORANGE | (GENRO+A)* | ||
| ROE | or could it be GOE? | ||
| DRAGONET | (GROANED+T)* | ||
| Down | |||
|---|---|---|---|
| SCALPEL | (PLACES+L)* | ||
| 1 | APACE | A+P+ACE | |
| 2 | LINEN | LINE+N | |
| 3 | LOG-SAW | L[OG’S]AW | |
| 4 | PERDURE | ER in PRUDE* | |
| GROANED | (ORANGE+D)* | ||
| PALE or SALE | (SEA+L)* | or (PEA+L)* | |
| 5 | ELLIE | ELL[I]E | |
| SEPAL | (PALE+S)* | or (SALE+P)* | |
| 8 | DETER | D TREE* | |
| 11 | IND | IN+D | the typo in the clue was obvious but seemed not out of place with all the other apparent mistakes. | 
| 15 | SPAROID | SPAR+O+ID | |
| 16 | OUTSPED | UT in DOPES* | |
| 18 | ASSUAGE | GAUSS< in A…E | |
| 19 | SALSA | SA[L]SA | sa sa is a call in fencing. | 
| 20 | VARROA | V+ARRO+A | ref. arrogate | 
| 21 | TEPEE | TE[PE]E | PE is the centre of prospector | 
| GENRO | (GORE+N)* | ||
| 23 | EYE | dd | |
| 24 | BOURG | amBO URGen | |
| 25 | BALAO | BALA+O | alternate letters of boat-load. | 
| GORE | (ROE+G)* | or could it be (GOE+R)*? | |
Hi Colin
There is a third option for the first sequence, pel-pale-sepal.
Thanks Geoff, and in that case there is a fourth: SEL -> SALE -> SEPAL
The solution has PEA and ROE. A comment elsewhere suggests that “seeds” were required for the two three letter words. I don’t remember anything in the preamble to support this even if there is a logic following from the title.
Probably my final comment on this one. It turns out that PEA has among its meanings ROE. So, both “seeds” are roe and both final words are fish, ESCALLOP and DRAGONET. I still feel the preamble is weak at best and the printed solution does not explain the link between the 3 and 8 letter words. However, even accepting the unstated constraints of the theme there is still an ambiguity in the solution. The printed solution has ROE -> NORE -> GENRO as the start of one sequence. The N or NORE is unchecked and so, as far as I can tell, ROE -> GORE -> GENRO is also a valid solution.