Burnettweldia californicordazi (agamic)

Burnettweldia plumbella (agamic)

Nichollsiella sulcata (agamic)

Burnettweldia washingtonensis (agamic)

Burnettweldia corallina (agamic)

Burnettweldia conalis (agamic)

Weldia californica, new species

Gall. Monothalamous bud or stem galls occurring singly or in groups of three to five; on current year's growth, if produced directly from stem, but, on two-year-old stem, if produced directly from terminal or axillary bud; galls produced from stems bear two, short, rounded projections at the point of attachment, one on each side of a groove occupied by the stem; galls produced from buds are circular at the point of attachment, often with bud scales clinging to gall base; subspherical in outline and flattened or even dimpled at apex (Q t californica [john-tuckeri]), surface mostly smooth with few irregularities; others circular, with low-level, rounded bumps over surface (Q douglasii). 

Internal structure: Mature galls contain a subcentral, oval, larval capsule composed of an inner, nutritive cell layer (may be indistinct in mature galls) and an outer, hardened, protective, sclerenchymal layer; capsulre surrounded by thick zone of large, loosely packed, columnar cells, more compressed and hardened just beneath epidermis; epidermis composed of thin, hardened layer of small, compressed cuboidal cells, two-to-three cells deep, appear crystalline in cross-section. 

Size: Average of 100 unparasitized galls: horizontal diameter, 12.2 mm; height, 11.6 mm.

[Type locality: San Bernardino CA]

Host records: Quercus douglasii, dumosa [berberidifolia? or possibly Q dumosa sensu strictu], Quercus turbinella californica [john-tuckeri] and various hybrids of these species and with other [white-group] oaks which are not hosts of W californica in the unhybridized condition. I have never seen galls of W californica on Q durata or lobata and only infrequently on Q dumosa where it occurs in the vicinity of either Q douglasii or Q t californica. 

Range: Known to occur only in California from San Diego Co north to Lake Co and probably around the northern rim of the San Joaquin Valley as well, wherever Q douglasii occurs.

Remarks: I at first thought this species to be Disholcaspis canescens while conducting biological studies on a large population at Cajon Pass. Later, I became aware that two distinct species, based on adults, were consistently placed together under D canescens in museum collections. This seemed peculiar since, with the exception of similar abdominal setation, the adults of both species are distinct. Bassett's type adult of D canescens matched the original description, but cotype galls did not and proved to be galls of W californica. Apparently, galls of D canescens, W corallina, and W californica were sent to Bassett in the same shipment from Napa CA and subsequently were mixed. The failure of later works, myself included, to correctly separate these species, is witness to the often misleading reliance placed on gall characteristics which may be only superficial.

Gall growth. Young galls of W californica first appear on Quercus turbinella californica [john-tuckeri] in mid-June as elongate evaginations of new stems or from terminal and axillary buds in which incipient stems were inhibited by early eclosion and larval feeding. These new galls are pale green and bear a dense coat of short, colorless pubescence which generally weathers away as they mature. Initial gall growth is rapid and by 1 August, they are approximately 7-8 mm in diameter, reddish green, and contain a thick-walled larval capsule composed entirely of moist, nutritive tissue closely surrounding the larva. By 15 September, galls are full-sized and average ca. 12 mm in diameter. The outer surface turns a deep red and the surface pubescence begins to weather away. The larval capsule, ca 3.5 mm in greatest diameter, is full-sized by this time and considerably larger than the third instar larva within. Galls are usually mature, medium brown and glabrous by 1 October. Internal tissue is dry and rust-colored and the mature, C-shaped larva completely fills the larval capsule. 

Four distinct zones of tissue, ie, epidermis, collenchyma, parenchyma and the sclerenchyma of the larval capsule, may be distinguished in sections through the mature galls. The inner nutritive layer of the larval capsule, the larval food source, is usually indistinguishable in mature galls.

Rearing adults. During October, 1974, mature galls were collected from oak branches at Site No 1 [26 miles northwest of San Bernardino] and maintained outdoors in rearing containers at Riverside, CA. Adult emergence in these containers began on 16 November and continued until 15 December. Emergences were most frequent in the early-morning hours and rare after midday. No emergence occurred on windy days of below-normal relative humidity. The largest number of emergences followed rain and/or periods of heavy fog.

Galls dissected, prior to normal emergence, exposed a variable degree of emergence-tunnel completion. The adult female chews an emergence tunnel leading from the larval capsule to the epidermis, through the side of the gall, midway between apex and the point of attachment to the stem. Many galls contained completed emergence tunnels except for a thin epidermal layer that separated the insect from the outside environment. During periods of subnormal relative humidity, females were found resting, sometimes for several days, just beneath this epidermal "window." Once she began chewing, the female could exit the gall within an hour. Many galls that bore no exit hole after the normal emergence period ended contained dead females in partially completed emergence tunnels. 

[Burnett gives a description of the results of oviposition experiments, detailing when and where the female oviposits]

Early egg eclosion occurs before new stems begin to grow beyond the bud scales and results in the complete inhibition of normal plant tissue development in the bud. Consequently, galls appear to arise directly from within the bud. On 27 May, such galls were 1-2 mm in diameter, pale green, and spherical with an apical red nipple. Buds become laterally distorted as galls enlarge to occupy the entire bud base. On 14 June, small galls were observed growing from buds on year-old wood, not growing directly from within a bud. Late eclosion occurring after new stem growth has begun results in true stem galls, as the eggs or larvae are carried away from the area of original egg deposition. 

[From key to galls, page 176 of the pdf] 

1. Subglobular stem and leaf petiole galls without apical projection or strong surface tubercles; surface may be smooth or bumpy

2. Stem galls on white oaks of the Pacific Slope from northern Baja California to points north; larval capsule spherical or oval, positioned centrally or basally in parenchymal tissue; under 14 mm in diameter.

3. Outline symmetrical, larger apically; larval capsule oval, basally positioned in parenchymal tissue; surface smooth or slightly bumpy; occurs in California on Q douglasii, Q dumosa, and Q turbinella californica [john-tuckeri]

Weldia plumbella, new combination

Disholcaspis plumbella
Adleria plumbella

Gall: Monothalamous bud or stem galls occurring singly or in clusters on young stems; stem galls bear an elongated groove at the point of attachment (an indentation made by the stem); bud galls bear a circular indentation at point of attachment (which corresponds to the shape of the bud base); most galls spherical, some with an apical projection 1 to 3 mm long, sharply pointed, others without such a projection; surface usually smooth, bare. 

Internal structure: Larval capsule spherical, centrally positioned in gall, composed of two layers, inner nutritive and outer protective layer; nutritive layer indistinct or absent in mature galls, outer layer thin; capsule surrounded by parenchymal tissue composed of elongate, woody columnar cells radiating away from point of attachment; flattened collenchymal zone positioned just below epidermis composed of compressed cuboidal cells; epidermins composed of small crystalline cells compressed into a thin lyaer 1 or 2 cells deep, forms hardened surface. Color: Growing galls pale green with whitish spots when in constant shade, shades of brilliant red or wine with yellow spots when constantly exposed to direct sunlight; mature galls light brown with pale yellow spots which are occassionally embossed, distributed uniformly over gall surface. Size: Average of 100 unparasitized galls: horizontal diameter, 10.6 mm, length of apical projection, 1.9 mm (galls without apical projections not included in the latter measurement). 

Galls of W plumbella vary considerably in size and in some populations 80% of galls lack the apical projection. Galls on Q turbinella californica [john-tuckeri] at desert margins are typically small (9 mm or less in diameter) with only an apical nipple or short, thin projection. Galls on Q dumosa, from Monterey Co northward, bear a long, stout apical projection to 3 mm or more in length. 

Hosts: Quercus dumosa, durata, and turbinella californica [john-tuckeri] 

Range: CA and northern Baja California

Gall Growth. New galls appeared on Q dumosa at Site No 2 [near San Bernardino] on 2 May 1974, and on Q t californica [john-tuckeri] at Site No. 1 [also near San Bernardino] ca mid-June. Small galls growing from within bud scales and later on new stems were pale green with reddish patches when exposed to the sun. At this time, many galls possessed a blunt apical projection. Galls which failed to exhibit this character were round and smooth apically at maturity. By 1 August, most galls at Site No 2 were approximately 5 mm in diameter and distinctly pointed apically with an orange-red background color and bright yellow spots. Galls growing on lower branches and shaded from direct sunlight were various shades of green with white or yellow spots. On 1 October, galls were full-sized (ca 10.5 mm in diameter), round, moist internally, and still vividly colored. By 10 November, they had weathered to a light tan and the yellow spots were either absent or subdued.

The internal structure of the mature galls is similar to that described for galls of [W californica](https://www.gallformers.org/gall/2523), however, the cells of the parenchyma are smaller and less elongate in W plumbella and the larval capsule is round and centered in the gall. In galls of W californica, the larval capsule is oval and subcentral. 

Old galls rarely are numerous on branches, as their attachment to stems is fragile and they are easily knocked to the ground by wind and rain. Frequently after a storm, 60-80% of the galls in an area (even those from which adults have not yet emerged) may be found lying on the ground, where they fall prey to birds and rodents which crack them open, apparently to eat the contained insects.

Galls arise from either terminal or axillary buds on the previous year's branch or from a new branch of the current year's growth. As with galls of W californica, W plumbella stem galls result when eggs in buds hatch after new stems have begun to grow. This causes the newly emerged first instar larva and its surrounding gall tissue to be carried with the stem as it grows. The mature stem gall may ultimatley rest several centimeters beyond the original site of oviposition. Bud galls result when eclosion occurs prior to incipient stem growth. Mature bud galls may be recognized by the presence of scales clinging to the gall base. 

Rearing Adults. Mature galls were collected from Q dumosa [berberidifolia?] near Site No 2 in September and October, 1974, and kept outdoors as rearing stock for oviposition experiments. Normal emergence of parthenogenetic females began on 7 October and continued until 21 November. 

[Burnett goes on to describe findings of dissections and oviposition experiments. 

[From key to galls, page 176 of the pdf] 

1. Spherical or cone-shaped stem galls, usually with an apical projection or strong surface tubercles

4. Surface smooth; pointed apically

5. Surface of mature galls brown or reddish with yellow spots (uniform light brown when weathered), smooth, usually with pointed apical projection; larval capsule central, spherical, thin-walled; on Q dumosa, durata, Q turbinella californica [john-tuckeri] and hybrids.

Weldia sulcata, new combination

Cynips sulcatus
Cynips sulcata
Disholcaspis sulcata

Gall: Monothalamous leaf-petiole galls occurring singly on leaves of [white-group] oaks; subglobular in outline, smaller galls spherical; surface of mature galls smooth; parenchymal tissue granular, loosely packed; larval capsule spherical, may be central or eccentric within gall, wall indistinct; growing galls light green when shaded, yellowish-red in direct sunlight; mature galls faded green to light brown on surface, light brown internally; not deciduous, but remain attached to leaf petiole and drop with leaves in fall. Horizontal diameter of 50 unparasitized galls 7.8 mm.

Although galls of W sulcata are known to occur only on the leaf petiole where it is attached to the stem, they are remarkably similar to those of W californica, in shape, surface and internal texture and color. The major differences are in the smaller size and often eccentric position of the larval capsule in galls of W sulcata. 

Host records: Quercus arizonica, oblongifolia, pungens, rugosa, toumeyi, turbinella turbinella, and undulata

Range: AZ and western NM. It probably occurs in northern Mexico as well, wherever its host ranges.

The galls I have examined in collections and in the field have all been monothalamous, containing a single larval capsule. Occasionally, two galls may coalesce and appear to be bithalamous, but this is rare.

[From key to galls, page 176 of the pdf] 

1. Subglobular stem and leaf petiole galls without apical projection or strong surface tubercles; surface may be smooth or bumpy

2. Leaf petiole galls on white oaks of Arizona and New Mexico; surface light brown, smooth; larval capsule spherical, irregularly positioned in parenchymal tissue, thin-walled; under 10 mm in diameter.



Weldia washingtonensis, new combination

Cynips washingtonensis
Disholcaspis washingtonensis

Gall: Monothalamous stem galls occurring singly on young stems; some mature galls spherical others oblate; surface of mature galls smooth, pebbled or somewhat wrinkled due to shrivelling; growing galls green or reddish with a long whitish pile which weathers away at maturity, mature galls medium brown, turning black with age; epidermis thin, brittle; parenchyma light brown, with large, parallel, columnar cells radiating away from larval capsule; larval capsule positioned in center of gall, oval, large, thick-walled, nutritive and protective layers usually distinct; weakly attached to stem by a small, circular projection allowing some galls to drop to the ground in severe weather. Horizontal diameter of 50 mature galls, 9.7 mm.

Galls of W washingtonensis, in their various forms, are occasionally difficult to separate from those of W californica and W plumbella (when the apical projection is absent) in outward appearance. However, in galls of W washingtonensis, the larval capsule is, without exception, centrally located (subcentral in W californica), large relative to gall size and oval (smaller and spherical in W plumbella). Growing and newly mature galls are covered with a long, whitish pile which turns rust-colored with age, a characteristic unique in the genus Weldia.

Galls are highly variable in size, shape, and epidermal sculpture which appears, at least in part, to be host related. For example, galls growing on Q garryana, near the summit of Liebre Mountain in northern Los Angeles Co., are small (5-8 mm in diameter), spherical and studded over the surface with numerous, blunt-tipped projections. At the same location, only 20-30 geet away, galls on Q dumosa are subspherical with an entirely smooth surface and average 3 mm larger in horizontal diameter. Adults from galls on the different hosts are not separable. If two species are represented by the different gall forms, I am unable to distinguish them using established taxonomic characters based on the few specimens at hand. All gall forms of W washingtonensis are similar internally and during the growing stage. 

Hosts: Quercus douglasii, dumosa, durata, garryana, and lobata. Quercus lobata records are questionable. I have not found galls of W washingtonensis to occur on any of the hundreds of "valley oak" inspected over the years since I first became interested in cynipid galls. But, on several occasions I have observed these galls on Q lobata X douglasii, many trees of which could easily have been casually taken for Q lobata.

Range: Weldia washingtonensis is the most widely distributed species in the genus. Known to occur from southern San Diego Co CA, more or less continuously, to Benton Co in northern WA, west of the Sierra Nevada and Cascade Mountains of the Pacific Slope. 

[From key to galls, page 176 of the pdf] 

1. Subglobular stem and leaf petiole galls without apical projection or strong surface tubercles; surface may be smooth or bumpy

2. Stem galls on white oaks of the Pacific Slope from northern Baja California to points north; larval capsule spherical or oval, positioned centrally or basally in parenchymal tissue; under 14 mm in diameter.

3. Compressed oval in outline; larval capsule large relative to gall size, oval, centrally positioned in parenchymal tissue; surface smooth (wrinkled or pebbled on Q garryana), with long whitish pile while growing; common on most white oaks from Baja California to Canada

Weldia corallina, new combination

Holcaspis corallinus
Holcaspis corallina
Disholcaspis coralline
Cynips corallina

Gall: Monothalamous stem galls occurring singly or in clusters of 2-4 on Q douglasii, numerous on some trees; basically globular in outline, some spherical, others dome-shaped at apex and truncate at base above point of attachment; surface of mature galls usually studded with blunt peg-like projections; in some galls the surface projections are reduced to regular rounded bumps or tubercles; parenchymal zone thick, hard, crystalline, reddish-pink; larval capsule thick-walled, oval, usually located in gall base just above point of attachment; new galls yellow-green, growing directly from young stems, coated with velvety, whitish, stellate pile which weathers off at maturity; full-sized galls red or wine colored, old galls black; not deciduous. Horizontal diameter of 100 unparasitized galls, 10.8 mm.

Two basic types of epidermal sculpture are observed in galls, one form with short, peglike projections uniformly distributed over the surfaace of rather spherical galls, the other type with large, rounded pumps or tubercles externally, more prominent at the base of dome-shaped or mushroom-shaped galls. These differences appear to be geographically related with the former occuring from Fresno Co in central CA, northward around the San Joaquin Valley rim and in areas of 1000-2000 feet or more in elevation. Galls with rounded bumps or tubercles occur south of central Fresno Co on the western slopes of the Sierra Nevada Mountains as far south as Tehachapi at elevations between 1500 and 3500 feet. As with galls of other species in the group, differences in epidermal sculpture may result from differences in moisture available to growing galls, depending on the amount of annual rainfall, host species, soil type, drainage, and other factors. 

Host: Quercus douglasii, durata, and garryana(?). It is possible that W corallina is hosted only by Q douglasii and its hybrid forms. 

Range: around the margin of the San Joaquin Valley

[From key to galls, page 176 of the pdf] 

1. Spherical or cone-shaped stem galls, usually with an apical projection or strong surface tubercles

4. Surface of mature galls deep red, studded with, more or less, uniform, blunt tubercles; parenchyma hard, crystalline; larval capsule basal; on Q douglasii and its hybrids.

Weldia conalis, new combination

Disholcaspis conalis

Gall: Monothalamous stem galls occurring singly or rarely in clusters of 2-5, never found on host tree in large numbers; conical in outline with entire gall drawn out to gradually tapering at apex, straight in some, bent over or lopsided in others; base above point of attachment abruptly flared and symmetrically spherical in some, irregluar and clasping stem in others; internally thin-walled, oval, larval capsule centrally positioned in the gall base at its broadest point and situated perpendicular to the galls vertical axis; parenchymal tissue soft, but dense (not woody); epidermal layer thin; surface basically smooth, slightly folded in some; color of growing galls pale green with short, white pile which turns reddish and weathers off at maturity; mature galls light brown, old galls dark brown to black; not deciduous. Average size of 50 unparasitized galls; horizontal diameter, 8.5 mm; height, 12.6 mm.

Hosts: Quercus garryana. No other hosts have been recorded, nor have I found galls on hybrids inspected near the type locality.

Range: Known only from a few locations of the western slopes of the Sierra Nevada Mountains in central CA. It is apparently not correspondingly distributed with its host Q garryana which ranges from the Liebre Mountains in northern Los Angeles Co to the Canadian border and beyond.

In mid July, 1976, new pale-green galls under 3 mm in diameter were observed bursting through the green bark of young Q garryana stems near Tollhouse CA. Other galls at the locality and at Sequoia Park were nearly full grown at this time, but still green in color and bearing a recumbent, whitish pile which was beginning to turn rusty red on larger galls. Fresh galls were growing directly from stems and none observed were associated with either terminal or axillary buds at that time. Large galls, those 8-10 mm high and 6-8 mm in diameter at the base, contained 3rd and 4th instar larvae housed in a moist, thick-walled larval capsule which later becomes so thin as to be barely noticeable in the dry mature galls. 

[From key to galls, page 176 of the pdf] 

1. Spherical or cone-shaped stem galls, usually with an apical projection or strong surface tubercles

4. Surface smooth; pointed apically

5. Entire gall drawn out into conical shape, broadened or clasping at base; green when young, light brown when mature; surface smooth or slightly longitudinally folded; larval capsule basal, oval; host specific to Q garryana in central California


Biosystematics of the new oak-gallwasp genus, Weldia, of western North America