Phylloxera caryaesepta

Hosts: Carya glabra, myristiciformis, texana, cordiformis, tomentosa x pallida

Elongate and slender or short and stout conical projections on both sides of leaf; light rose, crimson, yellowish-green, or light green and crimson towards apex; more convex above than below; elongate and slender galls with a diameter 2.0–4.0 mm; short and stout galls with a diameter of 5.0–12.0 mm; resembling either a thorn or sea anemone. An opening at apex on each side fringed with filaments.

Leaf gall: thorny

Range: AL, AR, FL, GA, LA, MS, OK, SC, TX, VA

Dactylosphaera caryae-septum, n. sp.
Gall No. 2

Hosts: Carya alba [tomentosa]

On the same leaves with the galls described above (No. 1) I found (June 7th) many presenting the following characters: Flattish, opening both above and below, in nipple-like projections, both surrounded by a downy substance, the upper opening being smaller and closer.

On opening the gall by a vertical cut, I observed a partly broken septum in the plane of the leaf, the border of the partition remaining, but the centre gone. A flat, dense, rim-like border extended around this septum into the parenchyma of the leaf, beyond the gall, so that the margins of the cut gall presented quite an acute angle. The greater part of the gall was above the leaf and its cavity was somewhat like two cones, with their bases together at the septum, the upper being much the larger. I opened one gall in which the inhabitants had perished when it was about one-fourth grown ; in this the partition was complete. Diameter .25 inch; inside diameter .08 inch; distance between the vertical orifices .15 inch.

Phylloxera caryae-foliae, Fitch, has a somewhat similar gall, but that opens only above, while the one under consideration opens both above and below, the principal opening being beneath.

Phylloxera caryaesepta (Shimer)

Galls of Carya alba (= ovata) have conical projections both above and below leaf, with nipple-like apices fringed with filaments when mature, the structure on both sides of the leaf somewhat resembling a miniature sea-anemone (diam. 5-12 mm). Colour of gall varies from pale yellowish green to red. Alatae emerge in late May-June from upper side of gall (Pergande 1904). In Illinois and Missouri, USA. On Carya glabra further east (New York, Virginia), the same or a closely-related species forms galls with a narrower conical structure above and below leaf (P. caryaesepta var. perforans; Pergande 1904). The life cycle is unknown.

Phylloxera caryaeseptem

Carya sp.
Conical or globose leaf galls with distinct orifice and containing aphids
Galls more or less conical above and beneath, opening on the upper surface, both nipples surrounded at the apex by a fringe of long filaments, walls thin, more or less transparent, diameter 5 to 12 mm, height 4 to 6 mm.

Phyhoxera caryae-septum (Shimer).

Dactylosphaera c.-septum
Phylloxera c.-septa

The galls of this species, especially those of the more typical form, are the handsomest and largest of this group. Their transverse diameter at the plane of the leaf ranges from 5 to 12 mm and their vertical diameter from 4 to 6 mm. They are quite convex on both sides and generally more conical and more prominently projecting above than beneath, especially so in the smaller specimens. All are provided with a nipple on both sides, the upper one stouter and more prominent, with its base more or less sunken below the plane of the gall. Both nipples, particularly the lower one, lean frequently somewhat towards one side. Both openings are either round or oval and fringed by about eight stout or slender filaments. The opening on the under side closes gradually so that the insects are compelled to leave from above. The consistency of the galls is dense, though rather thin, paper-like, and more or less transparent, crisp, and stoutest at the junction with the leaf. The cavity, if cut vertically, appears to be more or less hexagonal at the central portion, more or less pointed towards the nipples, and quite flat at the median circumference, with the exception of a ridge which indicates the former division of the gall into two compartments while young. The color above is variable. Some are of a darker or lighter bright red or pale rose, with a pale greenish margin around the base, while others are pale yellowish green, the nipple more or less brown, surrounded at base by a pale reddish ring. The color of the under side corresponds either more or less with that of the upper side or is of the same color as the leaf, or paler. In its younger stage, while still quite small, it is most beautiful and has very little resemblance to the fully grown gall.

The first observations regarding this gall were made May 13, 1883, and, as it will help to throw some light on the question of the formation of this and many other galls, I will here include the few notes made at the time. This gall, a very beautiful and curious object, I find, after a careful examination, to be nothing else but an abnormally great enlargement of a pore and the filaments or hairs surrounding same. From the position of the galls, there can be no doubt whatever but that the young insect, as soon as it finds a suitable place, stations itself directly over a pore on the under side of a young leaf, into which it inserts its proboscis to extract the sap and to remain in this position. The irritation, caused by the sucking, gradually enlarges the pore so that the insect can sink into the opening; the rapid growing of the leaf causes the walls of the pore to prolong and the thus formed cell to widen till a regular cell is formed, enclosing the insect completely.

Remarkable it is, however, that the irritation is not confined to the lower side of the leaf but that it extends also to the upper surface, to the opposite pore, producing a counterpart of that on the underside. Both sides of the young gall at this stage are regularly conical and are fringed at the apex of each cone by about eight or nine very long, slender, backward curved, fleshy filaments which, when compared with the hairs surrounding the other pores, prove them to be identical though greatly enlarged. When some of the galls were opened it was found that they were divided horizontally by a delicate membrane into two compartments in the lower one of which the young stem-mother, already mature at this date, and surrounded by some eggs, had established her home. With her was also found but one cast skin, which seemed to indicate that several skins had been cast before the gall had formed and closed. The color of the young gall above is quite pale green with the filaments bright cherry or pink. The lower side is darker and the filaments white. Two weeks later the galls had changed so completely in appearance that they could scarcely be recognized as belonging to the same species were it not for the filaments fringing the apex of the nipples, and even these were mere rudiments, much reduced by drying up. They were then fully mature and some of them already empty. When cut vertically it was observed that the dividing membrane had entirely disappeared, except the before- mentioned rudiment at the circumference.