Victor Mair has a post at the Log that is not only an impassioned ode to the Allium genus—”My uncontested favorite of all the Allium species, however, is garlic (Allium sativum)…”—but a treasure-trove of linguistic tidbits in both Chinese (he discusses jiǔcài 韭菜, “a kind of chive”) and English. I had known about ramps, “a kind of wild garlic… only available for six weeks in the spring,” but had not known the etymology, which is excellent. Bob Shackleton said in the comment thread: “And most wonderfully, we have here the English descendant of the original Indo-European word for onion (*krem-) – one of the few surviving relatives of Greek ‘kromion’!” The OED elaborates, in its entry for rams (which it takes as the original English form and which it refers you to if you look up ramp; the entry was updated in June 2008):
Cognate with Middle Low German rāmese, rēmese, Old High German ramese (German (chiefly regional) Rams, Rambs, Ramisch, Ramsche, Ramus, etc.; > Danish rams, †ramse (now chiefly regional, except in the synonymous compound ramsløg)), Norwegian rams (now regional, except in the synonymous compound ramslauk), Swedish rams, ramsk (c1580; now regional, except in the synonymous compound ramslök) < the same Indo-European base as Early Irish crem (Irish creamh), Welsh craf, cra, Lithuanian kermušė, Russian čeremša, all in sense ‘wild garlic’, and ancient Greek κρόμμυον, κρόμυον onion. Compare post-classical Latin ramusia (10th cent. in a German source probably ultimately of British origin), ramusium (c1025 in a British source), ramuscium (a1125 in a British source), all probably < Old English.
The β. forms [ram, rame] result from analysis of the α. forms as plural. It is uncertain whether the (rare) late Middle English forms show singular or plural forms; compare also ramsey n. and ramsons n.
In the thread, Piotr Gąsiorowski points out: “Ramson comes from the weak-noun plural hram(e)san, and ramsons is etymologically a double plural like children.” As for rampion (a name for several different plants), it’s entirely unrelated, with a complicated etymology of its own about which the OED goes on for paragraphs; a cognate is German Rapunzel—which I had no idea was primarily the name of a plant; I knew only the gal with the hair—and another is French raiponce, about which marie-lucie writes:
Looking up raiponce again on Wikipedia, I see that the Rapunzel of the story is called Raiponce in French, just like the plant. Having only read Grimm’s stories in English, I did not know the equivalent French name.
As for the origin of the French word, the TLFI (French online dictionary) gives raiponce as basically a borrowing from an Italian word attested as raponzo, raponzolo, raperonzolo, from Latin raponciolum (but the Latin word could be a learned reformation based on one of the Italian forms). The suffix -onz- seems to be unexplained in Italian, so the apparently basic word raponzo could be an adaptation of a word from another language, perhaps a Germanic one such as rapunze, the presumed stem of Rapunzel.
The OED says:
The Italian word has frequently been regarded as a derivative (formed with several suffixes) of rapa rape n.5 (see further Französisches etymol. Wörterbuch at rapum), but recent authoritative dictionaries of Italian consider this more likely to be a folk etymology (see e.g. M. Cortelazzo & P. Zolli Diz. etimol. della lingua italiana (ed. 2, 1999) at raperonzolo). Although post-classical Latin rapunculum, etc., has sometimes been suggested as the ulterior etymon of the plant name, it is much more likely to be an adaptation of one or more vernacular forms, given its late attestation and close formal resemblance to the latter.