Oh, my rusty hollyhocks!

As my wife knows, I don't have to be at work to get distracted by an interesting bug, plant or fungus. So, nobody was very surprised when, during a leisurely walk following a family pub lunch yesterday, I bent down to take a sample of an interesting-looking hollyhock (Alcea rosea) leaf.

Hollyhock leaf showing orange fungal structures and something small indicated by a red arrow...

As you can see from this photo, the leaf bears numerous orange fungal structures on both the blade and petiole (stalk), plus there's a small invertebrate indicated by the red arrow. Staring with the fungus, a closer look highlights some familiar structures...

Elongate orange fungal structures on the petiole. These are blister-like and the dark orange masses are spores that have become exposed as the blisters have ruptured.

On the leaf blade, similar (but more globular) spore-filled structures are seen (red arrows), while some appear greyer in colour (blue arrow).

Although small, these blisters clearly include some abnormal growth and colouration of the plant's tissues and thus can be considered to be galls. A quick look in Redfern & Shirley (2011) provides an easy identification - there is a single galling species species found on hollyhock (and some other Malvacaeae), the rust fungus  Puccinia malvacearum. This specimen clearly matches the description, including the grey colour of older spores. Although this species may be unfamiliar, the genus is found on many plants with those on lords-and-ladies (Arum maculatum) and nettles (Urtica dioica) being particularly common and widespread - just look out for the little orange rings and pustules. Now onto the potentially trickier tiny invertebrate...

Small (3 mm long) leafhopper on the hollyhock leaf. See below for the meaning of the red arrows and circle.

If you are familiar with generalist insect books such as Chinery (1986), you can quickly tell that this is a leafhopper (Cicadellidae) of some sort, possibly a relative of the often-illustrated Eupteryx aurata. However, there are numerous species in this group (the subfamily Typhlocybinae) and the more technical Le Quesne & Payne (1981) may well be needed to identify them by keying out. So, back to a bit of taxonomic morphology - important diagnostic features are as follows:

• The three apical forewing veins (indicated by red arrows in the above photo) join the same cell (indicated by the red circle), noting that two of the veins merge to form a 'Y'.
• In the same photo, you can see the white 'waxy area' on the front edge of the forewing. Just behind thisthere is an irregularly shaped black spot cut into two by a pale wing vein. In some species this spot marges into one.
• In side view the front of the face (running down to the piercing mouthparts) is flat without a clear angle part of the way down (see top photo below).
• The pattern on the pronotum is distinctive - two clear black dots near the front edge with fuzzy longitudinal brown marks attached to them, plus other smaller black dots to the sides (see lower photo).
• The pattern on the head shows a triangle of three large black spots; the single rear spot does not have a dent in its front edge.
• The front of the 'face' is not clearly shown here, but in the above photo you can just see that there are two more black spots in front of the three on the head, but not another pair further to the side by the eyes.

Side view of the leafhopper showing the flat front to the 'face'.

More-or-less dorsal view of the leafhopper showing the patterns on the head and pronotum.

Combining these features and using them in the key, the species can be identified as Eupteryx melissae. This is a leafhopper which, like the rust fungus above, is known from hollyhocks and related Malvaceae. It is very similar to E. thoulessi but can be separated using the features on the front of the face (E. thoulessi has the extra pair of lateral spots near the eyes which are absent here), and of course the food-plant is a helpful clue. Although this specimen was seen in mid-March, it is usually not recorded until May. However, it may have emerged following a recent spell of warm weather; when collected it appeared dead, but was probably simply torpid as the temperature had fallen considerably over a couple of days - certainly it became active again under the microscope.

More soon...

References

Chinery, M. (1986). Collins Guide to the Insects of Britain and Western Europe. Collins, London.
Le Quesne, W.J. & Payne, K.R. (1981). Cicadellidae (Typhlocybinae) with a checklist of the British Auchenorhyncha (Hemiptera, Homoptera). Royal Entomological Society Handbooks for the Identification of British Insects 2(2c): 1-95.
Redfern, M. & Shirley, P. (2011). British Plant Galls (2nd ed.). FSC, Shrewsbury.