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Full text of "Fifty common plant galls of the Chicago area"

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EB 1 1 1975 

DEC 4 ^98' 



O-1096 



"" ^"'''^ Of Tilt 






FIFTY COMMON PLANT GALLS 
OF THE CHICAGO AREA 



BY 
CARL F. GRONEMANN 



OCT J-5 




Botany 
Leaflet 16 



FIELD MUSEUM OF NATURAL HISTORY 
CHICAGO 

1930 



LIST OF BOTANICAL LEAFLETS ISSUED TO DATE 

Figs $ .10 

The Coco Palm 10 

Wheat 10 

Cacao 10 

A Fossil Flower 10 

The Cannon Ball Tree 10 

Spring Wild Flowers 25 

Spring and Early Summer Wild Flowers , . .25 

Summer Wild Flowers 25 

Autumn Flowers and Fruits 25 

Common Trees 25 

Poison Ivy 25 

Sugar and Sugar-Making 50 

Indian Corn 25 

Spices and Condiments 25 

Fifty Common Plant Galls of the Chicago Area .25 



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STEPHEN C. SIMMS. Director 



FIELD MUSEUM OF NATURAL HISTORY 
CHICAGO, U. S. A. 



LEAFLET 16 



FRONTISPIECE 




TWO EARLY KNOWN PLANT GALLS 
1. The Aleppo gall, Cynips tinetoria, as represented in Hortus aanitatis, 1491. 
Believed to be the oldest illustration of a gall. 2. Original illustration of the 
Aleppo gall, Cynipa tinetoria. 3. Illustration of the Chinese gall, Sehlechtendalia 
chinensis, from the Chinese Materia Medica, Pen ts'ao kang mu, about 1590. 
4. Original illustration of the Chinese gall, Sehlechtendalia ehinentis. 



OCT ^5 13:0 

Field Museum of Nat^iral History- ill' -'^• 



DEPARTMENT OF BOTANY 
Chicago. 1930 



Leaflet Number 16 
copykight 1930 by fleld museum op natural history 

Fifty Common Plant Galls of the 
Chicago Area' 

The curious swellings and bizarre formations called 
galls, which appear on plants, scarcely ever fail to attract 
attention, and their presence is often the cause of much 
speculation. Galls have long been known to exist, and we 
find mention of them in the literature of such early writers 
as Theophrastus (371-286 B.C.). Their origin, however, 
was unknown until comparatively recent times. For 
centuries it was believed that they were supernatural 
growths. In the Middle Ages the notion was prevalent 
that they might be consulted as omens, to foretell future 
events. It was thus believed that a gall containing an ant 
augured a bountiful harvest; a maggot, a plague among 
cattle; a spider, pestilence. Superstition associated with 
galls still prevails, at least in a small measure, in some 
countries. 

Early investigators were little concerned about the 
origin of galls. Apparently their interest was more in the 
practical value of them, particularly as a source of remedies 
for human ailments. 

The gall which has long held a foremost place in the 
practice of medicine, in tanning, dyeing, and in the making 
of ink, is the Aleppo gall (frontispiece), an oak gall found 
in Europe and Asia. An astringent decoction made from 

' Within fifty miles of the center of Chicago. 

[319] 



2 Field Museum op Natural History 

this gall was used in the treatment of ulcerated mouth, 
gum affections, burns, etc. Toothache was allayed by 
chewing the gall. While the use of the Aleppo gall for 
medicinal purposes has waned, it is still used extensively 
in tanning and dyeing and as an ingredient in the 
manufacture of writing fluids. 

Another gall, equally important and also used in medi- 
cine, tanning, and dyeing, is the Chinese gall (frontispiece), 
a sumac gall found in India, China, and Japan. The 
Bedeguar gall, a rose gall (p. 23), has long been used 
medicinally and as a charm to induce sleep. The use of 
galls as a basis for a dye employed in tattooing is recorded 
by Burton in First Foot-steps in East Africa, 1856. He 
found Somali women using them for that purpose. Thus 
we find that certain galls have had a wide range of useful- 
ness, both real and assumed. 

The Italian physician Marcello Malpighi (1628-94) was 
the earliest writer on galls to treat the subject system- 
atically, and it is he whom we must credit with the found- 
ing of this branch of the natural sciences, called Cecidology. 
Malpighi, finding that the galls under his observation were 
caused by insects, removed much doubt as to their origin. 

Although thousands of galls have been described from 
the United States, it is safe to say that there are thousands 
left to be discovered. To find galls one need not travel far. 
Often near-by woods, fields, and roadsides offer abundant 
material. Even the limited area of a city lot may not be 
entirely void of the plant deformations, for occasionally 
they are found on weeds and cultivated plants. 

Galls possess many interesting characters which tend to 
make 'them attractive study material. These features are, 
in the main, size, shape, texture, and a wide range of color 
— shades of green, yellow, brown, red, and white. 

[320] 



Fifty Common Plant Galls 8 

Plant galls caused by insects are due to a stimulus 
or irritation produced by them. The host plant responds 
to the action of this stimulus, which may be chemical or 
mechanical, by cell enlargement, new cells or both, thus 
giving rise to these abnormal growths. 

It was believed at one time that galls, particularly those 
caused by gall-wasps, resulted from a poison injected into 
the plant tissues by the insect at the time of depositing its 
egg. It is now generally conceded that gall formation 
does not usually occur until the larva has emerged from 
the egg. In the case of some galls caused by saw-flies, 
however, the galls commence to form before the larvae 
hatch. 

Not all galls are caused by insects. Some are due to the 
presence of eel-worms and still others to fungi, of which 
the cedar apple on the leaves of the red cedar is an out- 
standing example. 

The galls described in this leaflet are caused by members 
of the following orders of insects and their allies, the mites: 

Hemiptera (Aphididae and Psyllidae). Plant lice and 
jumping plant lice. 

Coleoptera (Cerambycidae). Longicorn beetles. 

Lepidoptera (Gelechiidae). Moths. 

Hymenoptera (Cynipidae and Tenthredinidae). Gall- 
wasps and saw-flies. 

Diptera (Itonididae and Trypetidae). Midges and 
peacock flies. 

Acarina (Eriophyidae). Mites. 

Birds, also, have an interest in galls because they are a 
source of a large part of their food supply. Chickadees and 
goldfinches search the willow cone gall for grasshopper 

[321] 



4 Field Museum of Natural History 

eggs often deposited there. Upon examining a willow cone 
gall which had previously been searched by a chickadee, 
103 grasshopper eggs were found. Woodpeckers and blue 
jays break open the oak bullet gall (p. 15) to get the gall 
insect. Squirrels search aphid galls like the petiole galls 
and the vagabond poplar gall (pp. 6, 7) for the honey-dew 
secreted by the gall makers, and also open the oak bullet 
gall to eat the insect. 

Among insects attracted by the saccharine fluid exuding 
from some galls, upon which they feed, are ants, beetles, 
and wasps. ^ 

Small spiders inhabit empty galls such as the succulent 
oak gall (p. 17), and the mason bee is known to build in the 
large empty oak apple (p. 10). 

Galls may be preserved by pressing and mounting like 
herbarium specimens, or they may be kept in a 2 per cent 
solution of formalin or a 50 per cent solution of alcohol. 
Hard, woody galls may be kept in pasteboard boxes. 

For other literature on the subject the reader is referred 
to the list of references at the end of this leaflet. 

In the descriptions of the various galls the name of the 
gall is in each case followed by the scientific name of 
the insect concerned in its production. 

^See Transactions, 111. State Academy of Science, 1926, p. 195. 



[322] 



Fifty Common Plant Galls 



PINE-GONE WILLOW 
GALL 

Rhabdophaga strobiloides (Walsh) 
MIDGE 

In this gall deformed leaves 
overlap each other, thus 
forming a scaly cone located 
terminally on twigs of the 
willows. 

Slightly pubescent and 
light gray in color. 

Arrow points to larval 
chamber. 





WILLOW LEAF GALL 

Pontania desmodioides (Walsh) 

SAW-FLY 

This smooth- or rough- 
surfaced gall appears on both 
sides of the leaf and fre- 
quently at the leaf margin. 
Occurs singly and in numbers 
to involve almost the entire 
leaf. 

Color: yellow-green, often 
tinged red. 



[823] 



Field Musexjm op Natural History 



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WILLOW APPLE GALL 

Pontania pomum (Walsh) 
SAW-FLY 

This spherical, fleshy gall 
occurs on the leaves of the 
willows. 

The major portion is on the 
under side of the leaf, pro- 
jecting but slightly above. 

Color: yellow-green, rosy- 
cheeked, with numerous small 
brown spots. 



I 



POPLAR PETIOLE GALL 

Pemphigus populitransversus{Iii\ey) 
PLANT LOUSE 

This oval gall, common on 
the Cottonwood, Populus 
deltoides, occurs about mid- 
way on one side of the petiole 
with a transverse slit on the 
opposite side. 

Color: green, often tinged 
red. 



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POPLAR STEM GALL 

Pemphigus populicaulis (Fitch) PLANT LOUSE 

This gall, also common on the cottonwood, is located at junction 
of petiole and blade. Opening at base slightly twisted. 

Color: like preceding. 

[324] 






Fifty Common Plant Galls 



VAGABOND POPLAR 
GALL 

Pemphigus vagabundtis (Walsh) 
PLANT LOUSE 

This apical gall is a de- 
formation of the leaves and 
is common on the cottonwood. 
It is hollow with an exit near 
the base as shown at A. 

B represents a young gall. 

Color: yellow-green, some- 
times tinged red. 





POPLAR TWIG GALL 

Saperda concolor (Lee.) 
LONGICORN BEETLE 

This irregular, elliptical 
twig gall occurs on both wil- 
lows and poplars and varies 
in diameter from one to three 
centimeters. 

Section of gall shown at A. 

Color: same as twig. 



[325] 



Field Museum op Natural History 




HICKORY ONION 
GALL 

Caryomyia holotricha (O. S.) 

MIDGE 

This very hairy gall occurs 
singly or closely massed on 
the under side of the leaves of 
several kinds of hickories. 

Color: pale when young, 
turning to rust-brown. 



HICKORY TUBE GALL 

Caryomyia tubicola (0. S.) 
MIDGE 

A small cylindrical gall 
occurring on the under side 
of hickory leaves. Constricted 
near the top. Apex slightly 
flaring. 

Color: young gall yellow- 
green, red near top, apex 
brown. Dark brown when 
old. 

B 

Cecidomyia sp. 

MIDGE 

This curved, tapering gall, slightly longer than the preceding, 
also occurs on the under side of hickory leaves. 

Color: green turning to dark brown. Lighter at base and apex. 
Above (A and B), enlarged galls. Below, natural size, 

[326] 




I 



Fifty Common Plant Galls 



HICKORY APHID GALL 

Phylloxera caryaecaulis (Fitch) 
PLANT LOUSE 

This hemispherical, hollow 
gall is among the largest 
found on hickories. It occurs 
on twigs, petioles, midribs 
and catkins. 

Opening at the top which 
gradually enlarges, the gall 
finally becoming cup-shaped 
as at D. 

Color: green, sometimes 
tinged red. 

A, on twig. B, on catkin. 
C, on midrib. D, on petiole, 
old and dry. 





HAZEL CATKIN GALL 

Ceddomyia squamulicola (Stebb.) 
MIDGE 

This gall is a deformation 
of the scales of the hazel cat- 
kin which have increased in 
size at the base. 

Color: same as catkin. 

Galls at A. 

Normal catkin at B. 



[327] 



10 



Field Museum of Natural History 




LARGE SPONGY OAK 
APPLE 

Amphibolips spongifica (0. S.) 
GALL-WASP 

A large, thin-walled, 
globose gall filled with a white 
spongy substance in the 
center of which is the larval 
cell. 

This gall occurs on the 
leaves of the black oak, 
Quercus velutina. 

Color: green, turning to 
light brown. 



LARGE EMPTY OAK 
APPLE 

Amphibolips inanis (O. S.) 
GALL-WASP 

In general outward appear- 
ance this gall is like the pre- 
ceding but is thinner walled. 
The larval cell is supported 
by radiating filaments. 

Occurs on the leaves of the 
red oak, Quercus horealis var. 
maxima. 

Color: green, with purplish 
spots. 

Another empty oak gall, 
Amphibolips cookii (Gill.) is 
represented on the cover of 
this publication. 




[328] 



Fifty Common Plant Galls 



11 



OAK CLUB GALL 

Callirhytis clavula (O. S.) 
GALL-WASP 

A hard, woody, club- 
shaped gall, which occurs on 
the tips of twigs of the white 
oak, Quercus alba. Leaves 
frequently grow from it. 

Contains several larval 
chambers. 

Color: green, often tinged 
red, turning brown. 





HORNED OAK GALL 

Callirhytis cornigera (O. S.) 
GALL-WASP 

This irregular spherical gall 
with its hornlike projections, 
each of which contains a 
larval cell, occurs on twigs of 
red oak, Quercus horealis var. 
maxima. It is hard and 
woody and variable in size. 

Color: like twig. 

A: section of enlarged 
larval cell. 



[329] 



12 



Field Museum of Natural History 




OAK ROSETTE GALL 

Andricus frondosa (Bass,) 
GALL-WASP 

This gall is a deformed leaf 
bud which has developed into 
a crowded mass of modified 
leaves. 

Occurs on the burr oak, 
Quercus macrocarpa, and the 
white oak, Q. alba. 

Color: green. 



OAK PETIOLE GALL 

Andricus petiolicola (Bass.) 
GALL-WASP 

This globose, slightly- 
spindle-shaped gall occurs at 
the base of the midrib of the 
leaves of the burr oak, 
Quercus macrocarpa, white 
oak, Q. alba, and swamp white 
oak, Q. bicolor. 

Contains several larval 
chambers as shown at A. 

Color: green, turning 
brown. 




[830] 



Fifty Common Plant Galls 



18 



WOOL SOWER GALL 

Callirhytis seminator (Harr.) 
GALL-WASP 

The wool sower is com- 
posed of a large number of 
small hairy galls attached to 
a common point on twigs of 
the white oak, Quercus alha, 
thus forming a compact 
woolly mass. A represents a 
single gall. 

Color: white, often tinged 
red, turning brown. 





SMALL OAK APPLE 

Andriciis singularis (Bass.) 
GALL-WASP 

A small, smooth, thin- 
walled, globular gall occur- 
ring on the leaves of the red 
oak, Quercus horealis var. 
maxima. 

It contains an oval larval 
cell suspended by radiating 
fibers. See A. 

Color: green, turning 
brown. 



[881] 



14 



Field Museum of Natural History 




CLUSTERED MIDRIB 
GALL 

Cynips nigricens (Gill.) 
GALL-WASP 

A small spherical gall found 
on the under side of the leaves 
of the white oak, Quercus 
alba, and the burr oak, Q. 
macrocarpa. Occurs in 
clusters on the midrib. 

Color: green, often tinged 
red, turning brown. 



LOBED OAK GALL 

Cynips strobilana (O. S.) 
GALL-WASP 

These angular, slightly 
wedge-shaped galls occur on 
the burr oak, Quercus macro- 
carpa, and the swamp white 
oak, Q. bicolor. Gall has a 
thick, corky wall. 

Color: green, turning 
brown. 

A: section of gall showing 
larval cell. 




[332] 



Fifty Common Plant Galls 



16 



RED-BANDED BULLET 
GALL 

Dryocosmus imbricariae (Ashmd.) 
GALL-WASP 

This smooth, spherical gall, 
irregularly banded with red 
and green, is found on twigs 
of several species of the red 
oak group. 

A shows section of gall. 





OAK BULLET GALL 

Disholcaspis globulus (Fitch) 
GALL-WASP 

This spherical, corky gall 
grows singly or in clusters on 
twigs of the white oak, 
Quercus alha. In the center of 
the gall is the small thin- 
walled larval cell. 

Color: yellow, tinged red, 
turning brown. 



[888] 



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16 



Field Museum of Natural History 




ROUGH BULLET GALL 

Disholcaspis mamma (Gill.) 
GALL-WASP 

This gall may be confused 
easily with the preceding. 
The distinguishing characters 
are a velvety surface and 
pointed apex. It usually 
occurs in large numbers and 
in variable sizes on the 
branches of the burr oak, 
Quercus macrocarpa. 

Section of gall at A. | 

Color: green, turning 
brown. 

■I 



WOOLLY LEAF GALL 

Callirhytis lanata (Gill.) 
GALL-WASP 

This gall, which occurs as a 
woolly mass on the under 
side of the leaves of several 
species of the red oak group, 
is composed of angular galls 
closely joined. When young 
the galls are covered with a 
whitish wool which later 
turns brown. 




[334] 



Fifty Cobjmon Plant Galls 



17 



SUCCULENT OAK GALL 

Dryophanta paliistris (O. S.) 
GALL-WASP 

This hollow, globular gall 
is found on the leaves and 
catkins of several species of 
the red oak group. In the 
young galls the larval cell is 
attached to the inner surface 
of the gall. Later it becomes 
detached and rolls about 
freely. See A. 

Color: green, often tinged 
red. 





OAK HEDGEHOG GALL 

Acraspis erinacei (Beutm.) 
GALL-WASP 

A hard, round or elongated 
gall the surface of which is 
separated into small conical 
facets terminating in slender 
spines. Occurs on the midrib 
of the leaves of the white oak, 
Quercus alha. 

Section of gall at A shows 
larval cells. 

Color: yellow-green with 
red spines. 



[836] 



18 



Field Museum of Natural History 



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OAK PILL GALL 

Cincticornia pilulae (Walsh) 
MIDGE 

A hard, subglobular gall 
often occurring in large num- 
bers on the upper surface of 
the leaves of several species 
of the red oak group. Surface 
of gall has numerous fine fis- 
sures which later break open 
and become ragged. 

Color: reddish. 



MARGINAL FOLD GALL 

Itonid foliora (Rssl. & Hkr.) 
MIDGE 

This gall is merely a fold- 
ing of the leaf's edge over on 
the upper surface. Occurs on 
several species of the red oak 
group. 

Color: like leaf, turning 
brown. 




[336] 



Fifty Common Plant Galls 



19 



COCKSCOMB ELM 
GALL 

Colopha ulmicola (Fitch) 
PLANT LOUSE 

This cockscomb-like gall 
is found on the upper surface 
of the leaves of the white elm, 
Ulmus americana. It is hol- 
low with an opening on the 
under side as shown at A. 

Color: green, often tinged 
red. 





SLIPPERY ELM POUCH 
GALL 

Pemphigus ulmifusus (Walsh) 
PLANT LOUSE 

A pouch-shaped gall occur- 
ring on the upper surface, 
usually near the midrib, on 
the leaves of the slippery elm, 
Ulmus fulva. Hollow, with 
opening on the under side. 
When mature, fissures occur 
at the base, thus providing 
additional exits for the insects. 

Color: green, turning 
brown. 



[337] 



20 



Field Museum op Natural History 




SPINY HACKBERRY 
GALL 

Cecidomyia spiniformis (Patt.) 
MIDGE 

This small conical gall often 
occurs in large numbers on 
the under side of the leaves 
of the hackberry, Celtis occi- 
dentalis. Hollow and thin- 
walled. 

Color: yellow-green. 



HACKBERRY NIPPLE 
GALL 

Pachypsylla mamma (Riley) 
JUMPING PLANT LOUSE 

This subcylindrical gall 
occurs on the under side of 
the leaves of the hackberry, 
Celtis occidentalis. Lower 
half slightly constricted. 
Rounded, pubescent apex. 
Represented on upper side of 
leaf by shallow depression. 
Enlarged section of gall at A 
shows larval chamber and exit 
channel. 

Color: pale blue-green. 




[338] 



Fifty Common Plant Galls 



21 



WITCH HAZEL CONE 
GALL 

Hormaphis hamamelidis (Fitch) 
PLANT LOUSE 

This conical gall occurs on 
the upper surface of the witch 
hazel, Hamamelis virginiana. 
It is often slightly constricted 
at the base. The opening is 
on the under side. 

Color: green, often tinged 
red. 





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SPINY WITCH HAZEL 
GALL 

Hormaphis spinosus (Shimer) 
PLANT LOUSE 

This gall, covered with 
numerous long spines, is a 
deformed fruit bud of the 
witch hazel, Hamamelis vir- 
giniana. It is hollow with 
an opening near the base. 

Color: green. 



[339] 



22 



Field Musexjm of Natural History 




CINQUEFOIL AXIL 
GALL 

Gonaspis potentillae (Bass.) 
GALL-WASP 

This hairy, spherical gall 
occurs in the axils of the leaves 
of the cinquefoil, Potentilla 
canadensis, modified leaves 
often growing from it. Con- 
tains an oval larval cell. 

Color: green, turning 
brown. 



SPINY ROSE GALL 

Rhodites pustulatoides (Beutm.) 
GALL-WASP 

This small, spiny gall 
occurs singly or in clusters on 
the leaves of some wild and 
cultivated roses. 

Color: green, tinged red, 
turning brown. 

A similar gall, Rhodites 
bicolor (Harr.), but larger 
and with long tapering spines, 
also is common. Occurs in 
clusters, often obliterating 
the leaf. 

Color: same as preceding. 




[340] 



Fifty Common Plant Galls 



23 



MOSSY ROSE GALL 
ROSE BEDEGUAR 

Rhodites rosae (Linn.) 
GALL-WASP 

This gall consists of several 
larval cells covered with fila- 
ments which give it the moss- 
like appearance. Imported 
accidentally into this country. 
Found on the sweetbrier rose, 
Rosa ruhiginosa. 

Color: green, often tinged 
red, turning brown. 




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[341] 



WILD CHERRY POUCH 
GALL 

Eriophyes padi (Nal.) 
MITE 

This small pouch gall 
occurs on the upper surface 
of the leaves of the wild 
cherry, Prunus serotina. 
When mature a fissure occurs 
which gradually widens and 
lays the gall open as shown at 
A. 

Color: green or red. 



24 



Field Museum of Natural History 




CHOKECHERRY 
POCKET GALL 

Contarinia virginianiae (Felt) 
MIDGE 

This gall is a deformed fruit 
of the chokecherry, Prunus 
virginiana, which has become 
swollen and elongated. The 
cherry stone is absent in the 
gall. Gall is shown at A. 

Color: green. 



WILD PLUM POUCH 
GALL 

Eriopkyes sp. 
MITE 

This elongated, irregularly 
swollen pouch gall often 
occurs in large numbers on 
the under side of the leaves 
of the wild plum, Prunus 
americana. 

Color: pale green, occasion- 
ally tinged red. 




[342] 



Fifty Common Plant Galls 



25 



BOX ELDER LEAF 
GALL 

Contarinia negundifolia (Felt) 
MIDGE 

This gall is an elongated, 
succulent, rolled swelling of 
the leaf on both sides of the 
midrib. 

Color: green. 

B 

Eriophyes negundi (Hodgk.) 
MITE 

Small warty swellings 
irregularly scattered over the 
upper surface of the leaves. 

Color: green. 





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GRAPE FILBERT GALL 

Schizomyia coryloides (Walsh) 
MIDGE 

This fusiform, hairy gall 
occurs in clusters on grape- 
vines. Pithy inside with a 
long narrow larval cell. 

A: single gall. 

B: section of gall showing 
larval cell. 

Color: green, turning 
brown. 



[343] 



26 



Field Museum op Natural History 




GRAPE 
PHYLLOXERA GALL | 

Phylloxera vitifoliae (Fitch) 
PLANT LOUSE 

This wart-like gall is 
present in large numbers on 
the leaves of wild and culti- 
vated grapes. Another gener- 
ation of this insect, found on 
the roots, is very destructive. 

A : an enlarged gall. | 

B: section of gall. I 

Color: green. 



ASH MIDRIB GALL 

Contarinia canadensis (Felt) 
MIDGE 

A rounded, elongated, suc- 
culent gall, occurring on the 
under side of the white ash, 
Fraxinus americana, leaves, 
involving midrib and part of 
leaf blade. 

Color: green, often tinged 
red. 




[344] 



Fifty Common Plant Galls 



27 



GOLDENROD BALL 

GALL 

Eurosta soUdaginis (Fitch) 
GALL-FLY 

A pithy, globular stem gall 
with an oval larval cell in the 
center. Usually one on stem, 
occasionally two or more. 
Common on the goldenrod, 
Solidago canadensis. 

Birds have been seen open- 
ing these galls to get the 
larvae. 

Color: green. 





ELLIPTICAL 
GOLDENROD GALL 

Gnorimoschema gallaesolidaginis 

(Riley) 

GALL-MOTH 

A hollow, spindle-shaped 
gall common on the stem of 
the goldenrod, Solidago cana- 
densis. Sometimes two or 
more on stem. Adult insect 
emerges through exit hole A 
previously prepared by the 
larva. 

Color: green, tinged red. 



[345] 



m 



28 



Field Museum of Natural History 




GOLDENROD BUNCH 
GALL 

Rhopalomyia solidaginis (Lw.) 
MIDGE 

A terminal gall arresting 
the growth of the stalk and 
causing the leaves to bunch 
together into a globular mass. 
The larval cell is at the end of 
the stalk in the center of this 
mass. 

Color: green. 



SUNFLOWER PURSE 
GALL 

Asphondylia globulus (0. S.) 
MIDGE 

This globular stem gall is 
common on the wild sun- 
flower, Helianthus giganteus. 
One or more on stem. The 
larval cells vary in number 
according to size of gall. 

Color: green. 




[346] 



Fifty Common Plant Galls 



29 



APICAL SUNFLOWER 
GALL 

Itonid sp. 
MIDGE 

This gall occurs terminally 
on the stem of the woodland 
sunflower, Helianthus divari- 
catus. A similar gall, caused 
by the midge Asphondylia 
helianthiflorae Felt, is found 
on Helianthus strumosus. 

Color: green. 





APICAL ROSINWEED 
GALL 

Aylax Uavenworthi (Bass.) 
GALL-WASP 

This apical, subglobular 
gall is a deformation of the 
leaves and stem and occurs 
on the rosinweeds, Silphium 
integrifolium and S. perfoli- 
atum. Illustration represents 
a gall on S. perfoliatum. It 
contains numerous larval 
cells. 

Color: green. 



I 

tt 



[847] 



OCT '5 u:o 



REFERENCES 

Beutenmuller, Wm The Insect-Galls of the Vicinity of New 

York City. Guide Leaflet No. 16, 1904. 
American Museum, New York, 

Cook, M. T The Insect Galls of Indiana. Twenty- 
ninth Annual Report of the Department 
of Geology and Natural Resources of 
Indiana, 1905. 
The Insect Galls of Michigan. Publica- 
tion No. I, Biological Series No. I, 
Michigan Geological and Biological 
Survey. 

Fagan, Margaret M The Uses of Insect Galls. The American 

Naturalist, Vol. LII, Feb.-March, 1918. 

Felt, E. P Key to American Insect Galls. New 

York State Museum Bulletin No. 200, 
1918. Albany, N.Y. 

KiNSEY, Alfred C Studies of Gall-Wasps (Cynipidae). 

Indiana University Studies, Blooming- 
ton, Ind. 

Kuster, Dr. Ernst Die Gallen der Pflanzen. Ein Lehrbuch 

fiir Botaniker und Entomologen. S. 
Hirzel, Leipzig, Germany. 

Ross, Dr. Herman Die Pflanzengallen Mittel- und Nord- 

europas. Gustav Fisher, Jena, 
Germany. 

Stebbins, Fannie A Insect Galls of Springfield, Mass., and 

Vicinity. Bulletin No. 2, 1910. Spring- 
field Museum of Natural History. 

SWANTON, E. W British Plant-Galls. A Classified Text- 
book of Cecidology. Methuen & Co., 
Ltd., London. 

Thompson, MiLLETT T An Illustrated Catalogue of American 

Insect Galls. 

Weld, Lewis H Cjoiipid Galls of the Chicago Area. Trans- 
actions of the Illinois State Academy 
of Science, Vol. XX, 1928. State 
Museum, Springfield, 111.