The moss calyptra is a small cap of gametophyte tissue that covers the apex of the moss sporophyte during its development. This little structure was the focus of my dissertation. Below is part of a figure that I used in my defense showing calyptra from several different moss species. The calyptrae are indicated by the orange arrows
This discussion may seem (ok) is pretty esoteric, but a reviewer on my last manuscript brought up this question. They proposed using calyptras as the plural of calyptra, rather than calyptrae. (Yes, these are the things that I think about for my job.)
This is part of the reviewer response that I sent to the editors regarding this question.
This is part of the reviewer response that I sent to the editors regarding this question.
We agree that there are challenges when adopting terms into other languages especially concerning the plural form of the word. The term calyptra is derived from the Greek word kalyptra, meaning veil or hood. The plural for the Greek word kalyptra is kalyptrai. However, with the change in spelling and its use in other languages the term has been latinized. Often Greek plurals ending in –ai are transformed into –ae (e.g., mycorrhizae, cypselae, thecae). Perhaps this was originally a spelling error, but at least in terms of the moss calyptra the –ae ending has persisted. In the two most widely used bryological glossaries (see references below) the plural form is cited as calyptrae and many papers and books use this plural form. I do not think that retaining this traditionally used plural form makes the study any less accessible to non-bryologists as there are other botanical terms that have similar plural forms. Thus, we would prefer to continue to use calyptrae as the plural form in our manuscript. Additionally, switching to an –s ending would require additional explanation, which is outside of the manuscript’s focus.
Thanks to my colleague Nic Tippery who contributed to this explanation and I consult on all words Greek and Latin.