The following species have been reported for Indiana but have been excluded for want of satisfactory evidence to warrant their inclusion: The reasons for exclusion are discussed under the name of the species. It is needless to say that critical examination has been given doubtful species, and doubtful records, and every effort possible has been made to validate them.
Pinus echinàta Miller. Short-leaf Pine. This species does not occur in our area and all reference to it should be transferred to Pinus virginiana. References to this species are instances of wrong determination.
Pinus resinòsa Aiton. Norway Pine. This species was reported as an escape in Wabash County by Coulter[72] for Jenkins.
Pinus rígida Miller. Pitch Pine. Baird and Taylor[73] reported this species for Clark County. The range of this species is to the east of our area. They also reported Pinus Strobus, which has not been seen since they reported it, and they failed to report Pinus virginiana which is a common tree on the "knobs" of Clark County. A study of their flora of Clark County shows that they did little or no collecting in the "knobs." They also freely reported field crop, garden and flower escapes, and it is believed that their reference to Pinus rigida and Pinus Strobus should be regarded as to cultivated trees.
Àbies balsàmea (Linnæus.) Miller. Balsam Fir. Heimlich[74] reports this as occurring in Porter County about Dune Park. He cites for his authority Bot. Gaz. Vol. 27: Apr. 1899. The article referred to is Cowles' article on the flora of the sand dunes of Lake Michigan, in which he discusses the flora from Glen Haven in northern Michigan to Dune Park, Indiana in Porter County, which has confused Heimlich in separating the trees reported at several stations. It has never been found in Indiana.
Chamæcyparis thyoìdes (Linnæus) Britton, Sterns and Poggenberg. White Cedar. The range of this species is east of the Alleghany mountains and no doubt was never native in our area. The first reference to it is by Dr. Drake in his Picture of Cincinnati, published in 1815, page 83, in which he says: "The White Cedar and Cypress are found on the banks of the Wabash." Schneck[75] in his Flora of the Lower Wabash Valley says: "Wet places near the mouth of the Wabash River." I am certain it is not on the Indiana side of the river. Gorby[76] reports it for Miami County. All of his botanical records are too unreliable to receive serious consideration. Coulter[77] reports it as found in Allen County on the authority of Dr. C. R. Dryer. I saw Dr. Dryer recently and he says he has no recollections about it.
Juniperus commùnis Linnæus. Juniper. This species has been reported from all parts of the State. The distribution of the species is to the north of Indiana, and examining herbarium specimens it is found that subulate forms of Juniperus virginiana are frequently named Juniperus communis. In the older floras it was a custom to include cultivated forms, and not distinguish them as such. Since juniper has been for years a common ornamental shrub, especially in cemeteries, it is highly probable that many records have such a basis. It is proposed to drop this species from our flora. I refer Higley and Raddin's[78] record to the decumbent variety. VanGorder's and Bradner's records may also be the decumbent form. Heimlich's record I regard as an error, see remarks under Abies balsamea.
Populus balsamífera Linnæus. Balsam Poplar. This species was reported by Bradner for Steuben County. In a letter from the late Prof. Bradner, he said he had no specimen and had no recollection of the tree. J. M. Coulter reported it for Jefferson County, but Young who also wrote a flora of Jefferson County does not mention it. Baird and Taylor also reported it for Clark County. The last two records may have been from cultivated trees or mistaken for Populus grandidentata which was not reported and is in the area, and is a frequent tree in the "knobs" in Clark County. Heimlich reports it in Proc. Ind. Acad. Sci. 1917:404:1918 for Cowles. I regard this as an error. See discussion under Abies canadensis on page 290. Since the range of the species is to the north of Indiana, it is here proposed to drop it from our flora. It should be looked for on the "divide" in Steuben County and about Lake Michigan.
Populus cándicans Aiton. Balm of Gilead. This species has been included in a few local floras, but it is believed that it has not yet escaped from cultivation. Phinney[79] gives it as "an important timber tree of Delaware County," which is an error.