The word "tuckahoe" is used in at least three distinct senses among North American English speakers.
"Tuckahoe" is often said to be the English rendering of an "Algonquin word". While most of the Native Americans along the eastern seaboard spoke one of the Algonquin languages, those languages varied greatly. It seems unlikely that an Algonquin word would appear in many of these languages, referring to the same thing, and using the same pronunciation that it would be rendered in English in the same way, over such a broad area. The following summarizes some of the information that's available on the web concerning the use of this word.
Arrow Root The earliest mention of "tuckahoe" by English speakers is in "A History of Virginia" by Captain John Smith of the Jamestown plantation, and published in 1612.
Smith's description is echoed by a later writer:
Out of the ground they dig trubs earth nuts wild onions and a tuberous root they call tuckahoe which while crude is of a very hot and virulent quality, but they can manage it so as in case of necessity to make bread of it just as the East Indians and those of Egypt are said to do of colocassia or the West Indians of cassava It grows like a flag in the miry marshes having roots of the magnitude and taste of Irish potatoes which are easy to be dug up. source:Beveley, 1722
It is not clear from Smith's writing whether the term "tockawhoughe" is the Indian name for the plant, or simple a descriptive term that they used for any of several similar species the Indians used for food. The word is sometimes translated as "it is round" which may refer to the shape of the edible tuber. Other definitions include "reduced to flour" or "pound it into flour".
Respecting the frequent diet of the Indians in general we may say that besides their usual plantations of corn, pumpkins, squashes &c they often used wilds roots and wild fruits among the latter were chestnuts shellbarks walnuts persimons huckleberries &c of the roots they had hopniss (glycine apios) katniss (sagittaria sagittifolia), tawho (arum virginicum), tawfcee (orantium aquaticum). These roots generally grew in low damp grounds were a kind of potatoes to them and were divested of their poisonous or injurious quality by roasting them in the fire.
To which Source:Bolton, 1848 added, commenting on the above,
The Mohegan term for bread is Tauquah. These names evidently point to one and the same plant which still flourishes along the moist margins of the Tuckahoe creek [in the Bronx, New York]...The name Tuckahoe means in the Algonquin "The Bread" literally Tuckah bread the o oe or ong being merely an objective sign relating to the plant itself".
From this we can probably conclude that "tuckahoe", in one form or another, did indeed occur in many Algonquian languages, and probably referred not to a single species, but a variety of marsh species, all with an edible root that had to be processed to make it palatable, and which was normally ground into a flour for use such as making bread.
The Tuckahoe Potato...is evidently a member of the family of fungi which consists of plants that are considered by Gray as upon and drawing their nourishment from living though more commonly languishing and animals or else as appropriating the organized matter of dead and decaying animal and vegetable bodies...The Tuckahoe is interesting to a Historical Society as being one of the productions indigenous to the soil of Virginia described by Capt Jno Smith. From Historical Magazine, IV(2):53 Notes and Queries:Tuckahoe Potato. (Feb. 1865)
Whatever Jefferson thought, it seems very unlikely that "tockawhoughe" refers in fact to black truffles, (or any other fungus for that matter). Smith makes it clear that "tockawhoughe" is a marsh species. Truffles on the otherhand grow on the roots of various tree's (e.g., oak, beech, etc.) and would not be found in a marsh setting. Additionally, Smith describes them as being a major source of food for the Indians. While truffles are, of course, edible, their abundance is not such that they could form a major portion of anyone's diet. Arrow arum, on the other hand is widespread through freshwater marshes of the eastern United States. Finally, Smith also makes it clear that "tockawhoughe" has to be heat processed to be edible; that is not the case with truffles, but is true of arrow arum.
The follow observation was made by Peter Kalm, in his Travels in North America, (in Source:Pinkerton, 1812:468) and seems to close the book on the idea that Tuckahoe might be Jefferson's truffles:
Mr Bartram had some truffles or Linnœus's lycoperdon tuber which he had got out of a fandy soil in New Jersey where they are abundant These he shewed to his friend from Carolina and asked him whether they were the tuckahoo of the Indians. But the stranger denied it, and added that though these truffles were likewife very common in Carolina yet he had never seen them used any other way but in milk against the dysentery and he gave us the following description of the tuckahoo. It grows in several swamps and marines and is commonly plentiful. The hogs greedily dig up its roots with their noses in such places  and the Indians in Carolina likewise gather them in their rambles in the woods dry them in the sunshine, grind them, and bake bread of them. Whilst the root is fresh it is harsh and acrid but being dried it loses the greatest part of its acrimony. To judge by these qualities the tuckalioo may very likely be the arum virginianum.
In some instances the name is translated as a descriptive name such as "round tuber", or "place where tubers grow". This may account for the fact that different plant species are described as "tuckahoe"; as a descriptive, rather than botanical name, tuckahoe could apply to a variety of different species.
The Geographical Name Inventory System of the U.S. Geological Service systematically captures place name data throughout the United States. This system was searched for the occurrence of place names including "Tuckahoe" or "Tuckaho". Raw data from the extraction are given at the bottom of the article. A tabular summary of the frequency of occurrence is given immediately below this section. A total of 92 instances of the use of these words in placenames was noted, either as the common name for a place, or as an alternative name.
Note that the frequency with which these words appear is at its peak within the State of Virginia, dropping off with increased distance from this epicenter.
The following data was extracted from the GNIS system, 24 August 2009. These data were used in the foregoing analysis of the distribution of the word "Tuckahoe" or "Tuckaho".
*Tuckaho or Tuckahoe is listed as an alternate name for this location.
1. The name "Tuckahoe" derives from the Algonquin word "ptuckweoo," which directly translates to "it is round," but was more commonly used to describe the aquatic and bog plants that provided starch in the diet of American Indians. Tuckahoe
2. The common use of the word Tuckahoe in literature is its reference to bread, bread substitutes or plants from which bread could be made. The Algonquians used many aquatic and bog plants having tubers rich in starch for such purposes. Some of the more popular ones were arrow arum (Peltandra virginica), sweet flag (Acorus calamas), golden club (Orontium aquaicum), and Jack-in-the-pulpit (Arisaema sp.). Jack-in-the-pulpits were so plentiful that a young single brave could collect a week's supply of this kind of food for the entire village in only one day. These tubers were cooked in a pit located beneath a fire for 24 hours before eating them. All of these plants were later grouped under the term Tuckahoe. For many years the term Tuckahoe was given to several similar-appearing fungi, especially the smaller puff balls (Lycoperdon) and the larger puff balls Tuckahoe is a mushroom! (Cavatia).
and (getting a bit bizarre)
3. As we look further back in history we find that the Blue Ridge Mountains divide the anchient Algonquin domain into two nations, the Ptuckweoos to the east and the Quohees to the west. The Quohees turned their noses up at the easterners because they fed upon ptuckweoos, which they dug from the earth, thus calling them mushroom eaters or ptuckweoos. Tuckahoe is a mushroom! (Cavatia).
and more from the same source:
4. The reference to being a 'Tuckahoe Indian' is an old Native American inside joke. Sort of an inside the family insult. There is no tribe called Tuckahoe, it refers to all Algonquian speakers East of the Blue Ridge Mountians.
5. The Algonquians in the West ate different foods than the ones in the East. The ones in the West considered the ones in the East rather backward and well, a little bit stupid. The word 'ptuckweoo' in Western dialects means 'it is round', ie bread. When you refered to an Eastern Algonquian speaker and said he is ptuckweoo, your are refering to him as an eater of something round, ie mushrooms,fungus, mushrooms grow in poop, etc.etc. Melungeon mailing List Archives
6. Tuckahoe town of East Chester is from "Ptuckweoo" It is round It was the name of a bulbous root which was used by the Indians for food and for making bread or round loaves Indian Geographical Names
7. Thomas Hariot gave a very similar description of a plant he called Cocushaw, which was used by the Indians of North Carolina, and which “groweth in very muddie pooles and moist groundes”: The juice of this root is poison, and therefore heede must be taken before any thing be made therewithall: Either the rootes must bee first sliced and dried in the Sunne, or by the fire, and then being pounded into floure wil make good bread: or els while they are greene they are to bee pared, cut into pieces and stampt; loves of the same to be laid neere or over the fire untill it be soure, and then being well pounded againe, bread, or spone meate very good in taste, and holesome may be made thereof (Quinn 1991 :349).
None of our accounts of the Lenape mentions the eating of marsh roots, but since the large marshes around the Delaware Bay abound in such plants, it would surprising if they were not exploited, and the siting of prehistoric sites near marshlands suggests that they may have been important food sources in earlier times. http://deldot.gov/archaeology/puncheon_run/pdf/august2005/VOL1-2005-PDF/08_chapter5-FINAL-eda.pdf Delaware DOT]
8. edible plant root, 1612, Amer.Eng., from Powhatan (Algonquian) tockawhoughe (cf. Mohegan tquogh, Shawnee tukwhah), perhaps related to Cree (Algonquian) pitikwaw "made round." OnLine Dictionary
9. Etymology: Virginia Algonquian tockawhoughe
10: tuckahoe tockawhoughe reduced to flour
11: The species Wolfiporia cocos and Polyporus tuberaster have often been discussed together precisely because each has an association with stone. First, let’s consider Wolfiporia. The sclerotium (a hardened mass of underground mycelium) of this fungus has been known for several hundred years as “tuckahoe” or “Indian bread.” The word “tuckahoe” – rendered variously as tockawhoughe, tawkee, or tuckah – has its origin in an Algonquin language and means “it is round.” White settlers of the British colonies called this sizable sclerotium “Indian bread” because some native Americans dug it up and roasted it or ground it into meal. Until the 20th century, the botanical identity of the tuckahoe and its use by native American cultures has been subject to some uncertainty and misinterpretation. The confusion stems from the fact that “tuckahoe” has also referred to a host of tuberous plants, like the Virginia Wake Robin (Arum virginicum) and Golden Club (Orontium aquaticum) which have also served as foodstuffs. Notes from Underground - by David Rose. Tuckahoe and Fungus Stone This column originally appeared in the Spring 2000 issue of Spores Illustrated, the newsletter of the Connecticut-Westchester Mycological Association (COMA).
12:From Powhatan tockawhoughe/tockwhough/taccaho, "root used for bread", reconstituted as takwahah/ (perhaps from Proto-Algonquian *takwah-, "pound (it)/reduce (it) to flouer"). Wikipedia
13. Treaty Between Virginia And The Indians dated 1677, go to http://www.baylink.org/Pamunkey/. This site is the home page of the Pamunkey Indians, of Virginia. In section VII of the Treaty it states the following. Note: All mispelled words are as written, per the original document of 1677.
VII. That the said Indians have and enjoy theire wonted convenieces of Osytering, fishing, and gathering Tuccahoe, Curtenemmons, wild oats, rushes, Puckoone, or any thing else for their natural Support not usefull to the English, upon the English Devidends, Alwayes provided they first repaire to some publique Magistrate of good Repute & informe him of their number and business, whoe shall not refuse them a certificate upon this, or any other Lawfull occasion, soe that they make due returne therof when they come back and goe directly home about their business without wearing or carrying any manner of weapon, or lodging under any Englishman's dwelling house on night. Saponi Town Forum
14. From Historical Magazine, IV(2):53 Notes and Queries:Tuckahoe Potato. (Feb. 1865)
The Tuckahoe Potato represented as being occasionally found in George's County Va and in tho counties of Stafford and Westmoreland habitat is mostly marshy ground although occasionally found in the woods and open fields Wherever it grows however it is always found under the ground The donor refers the Society to certain articles of the Planter that have been written on the subject but as the committee has no access to the volumes of that journal the report upou this vegetable production is prepared entirely from an examination of the article itself It is fusiform in shape tapering quite abruptly at one end and very gradually toward the other eleven inches in length and 2J inches in thickness at the largest portion At four places there are abrupt diminutions of the thickness which gives tho whole the appearance of being composed of five different tubers and each one seems like an excrescence on neighbor these five portions may be considered as different stages of growth of Tuckahoe Exteriorly it is of a dirty yellow color sulcate and wrinkled with tough hard epidermis Attached to the portion and evidently that on which it grown is a knot of the pine which seems have been attached to a limb Internally it composed of a yellowish white friable mass light and spongy contrasting in specific very markedly with the heavy cortical covering The taste is slightly bitter and acrid
It is evidently a member of the family of fungi which consists of plants that are considered by Gray as upon and drawing their nourishment from living though more commonly languishing and animals or else as appropriating the organized matter of dead and decaying animal and vegetable bodies These originate in the formation of small threads and act as roots for obtaining food for the fungus and which constitute what is called Uiomycelium Upou these threads are formed the different shapes which the large family of fungi possesses which in this case are as before said tuberous in form In the case of the mushroom a thick stalk stipes appears on the mycelium which bears a rounded cap pileus and the lower surface of the pileu consists of parallel folds or plates constituting the hymenium The Tuckahoe differs from the mushroom in the hymenium being concrete with the substance of the pileus. The Tuckahoe most likely belongs to the genos Polyporns that furnishes the white agaric P officinalis of the shops The latter comes from the Levant where it grows upon the stem of the larch tree in a semi conical shape Its medicinal qualities are emetic and cathartic and an external application to bleeding wounds show thut it has some styptic properties The ordinary spunk tinder or amadou is a member of the same genus P fomcntarius
The Tuckahoe is interesting to a Historical Society as being one of the productions indigenous to the soil of Virginia described by Capt Jno Smith He says
The chiefe root they have for food is called Tockawhoughe. It groweth like a flagge in marishes. In one day a Salvage will gather sufficient for a week. These rootes are much of the greatness and taste of Potatoes They use to cover a great many of them with Oke leaves and Ferne and tlien cover all with earth in the manner of a Colepit over it on each side continuo a great fire for 24 houres before dare eat it Raw it is no better than poyson and being rested except it be tender and heat abated or sliced and dryed in the Sunne mixed with sorrell and meale or such like will prickle and tormeut the throat extreamely and yet in sommer they use this ordinarily for bread Smith's History of Virginia i 123
Mr Bartram had fome truffles or Linnœus's lycoperdon tuber which he had got out of a fandy foil in New Jerfey where they are abundant Thefe he hewed to his friend from Carolina and aflced him whether they were the tuckahoo of the Indians But the ftranger denied it and added that though thefe truffles were likewife very common in Carolina yet he had never feen them ufed any other way but in milk againft the dyfentery and he gave us the following defcription of the tuckahoo It grows in feveral fwamps and marines and is commonly plentiful The hogs greedily dig up its roots with their noies in fuch places and the Indians in Carolina likewife gather them in their rambles in the woods dry them in the fun mine grind them and bake bread of them Whilft the root is freih it is harfli and acrid but being dried it lofes the greateft part of its acrimony To judge by thefe qualities the tuckalioo may very likely be the arum virginianum Compare with this account what ihall be related in the fequel of the tahim and tuckah
Tawho and tawhim was the Indian name of another plant the root of which they eat Some of them likewife call it tuckah but moil of the Swedes ftill knew it by the name of taw ho It grows in moift ground and fwamps Hogs are very greedy of the roots and grow very fat by feeding on them Therefore they often vifit the places where thefe roots grow and they are frequently feen rooting up the mud and falling with their whole body into the water fo that only a little of the back part was out of the water It is therefore very plain that thefe roots muft have been extirpated in places which are frequented by hogs The roots often grow to the thicknefs of a man's thigh When they are frem they have a pungent tafte and are reckoned a poifon in that frefh ftate Nor did the Indians ever venture to eat them raw but prepared them in the following manner They gathered a great heap of these roots dug a great long hole fometimes two or three fathoms and upwards in length into which they put the roots and covered them with the earth that had been taken out of the hole they made a great fire above it which burnt till they thought proper to remove it and then they dug up the roots and confumed them with great avidity Thefe roots when prepared in this manner I am told tafte like potatoes The Indians never dry and preferve them but always take them freih out of the marihes when they want them This taw ho is the arum Virginicum or Virginian wake robin It is remarkable that the arums with the plants next akin to them a re eaten by men in different parts of the world though their roots when raw have a fiery pungent tafte and are almoft poifonous in that ftate How can men have learnt that plants fo extremely oppofite to our nature were eatable and that their poifon which bums on the tongue can be conquered by fire. Thus the root of the cala palustris which grows in the north of Europe is sometimes used instead of bread on an exigency The North American Indians consume this species of arum. Those of South America and of the Weft Indies eat other species of arums The Hottentots at the Cape of Good Hope in Africa prepare bread from a species of arum or wake robin which is as burning and poisonous as the other species of this plant In the same manner they employ the roots of feme kinds of arum as a food in Egypt and Afia Probably that fevere but sometimes useful mistress necesity has first taught men to find out a food which the first taste would have rejected as useless This taw ho seems to be the same with what the Indians in Carolina call tuckahoo
Taw kee is another plant fo called by the Indians who eat it. Some of them call it taw kim and others tackvim. The Swedes call it always by the name of taw kee The plant grows in marishes near moist and low grounds and is very plentiful in North America. The cattle, hogs, and stags are very fond of the leaves in spring for they are some of the earliest. The leaves are broad like those of the convallaria or lilly of the valley green on the upper fide and covered with very minute hair fo that they looked like a fine velvet The lndians pluck the seeds and keep them for eating They cannot be eaten fresh or raw but must be dried The Indians were forced to boil them repeatedly in water before they were fit for use and then they ate them like pease When the Swedes gave them butter or milk they boiled or broiled the seeds in it. Sometimes they employ these seeds instead of bread and they taste like pease. Some of the Swedes likewise ate them and the old men among them told me they liked this food better than any of the other plants which the Indians formerly made use of. This taw kee was the orontium aquaticum