“Estimated high UV later in the week.” Eloise frowned slightly and glanced up. “I think we ought to up-regulate.” She crossed the room to the lichen interface and tapped on the screen.

Tasneem looked up. “Auto not recommending?”

“Mmm. No. But it’s been reasonably high anyway, and last time there was a high few days the photobiont suffered.”

“Okay, I trust you, if you think it’s best.”

Eloise programmed in increased UV protection and pressed send. The interface sent out the electromagnetic pulses that prompted the lichen structure to produce higher levels of parietin and melanin in its tissues, which would help protect the structure and its associated algae and cyanobacteria. And help keep the inside cool, too.

She looked up. The morning sun was a glow through the lichen, picking out areas less full of photosynthetic cells. She stroked the wall gently. Eloise loved the lichen. In a mode of housing where the quality of your home infrastructure depended on how much attention you gave it, theirs did well. Lichen houses had become more popular in recent years where the prevailing weather was feasible for them. The ones here were × Xanthigera, an artificial hybrid of the fungi that formed the yellow Xanthoria parietina lichens common on stonework and trees (highly tolerant of nitrogen deposition and other air pollution, which is why they thrived where other species died off) and a Peltigera species, a dogtooth lichen that formed large thalli on mossy ground.

Eloise liked the name ‘dogtooth’; it was wonderfully descriptive and a bit fanciful, describing the root-like rhizoids on the lower side of the lichens that helped to anchor them to the ground. Eloise sometimes came across them while walking, and it blew her mind a bit to think that these little organisms were related to the structure she lived in, that working with fungi could bring about such a partnership between humans, fungi, algae and cyanobacteria… and all the other bacteria and viruses and invertebrates that interacted with and through the lichen.

Like other lichens, the thallus – the body of the lichen – was made up of fungus, forming a protective skin over a spongy layer that housed the photosynthetic partners: the single-celled organisms that harvested the energy from sunlight, feeding the fungus which housed and protected them and provided them with nutrients. In summer, they also provided the human inhabitants with sugars when they were producing enough, and a certain amount of the algae themselves, distributed throughout the upper surface, could be harvested too. Eloise and her partner provided water and nutrients when needed, though the lichen was low maintenance from that angle. The delicate part was growing the thallus over the framework in the first place.

A blip in the interface caught her eye. Her brow furrowed. “The house isn’t happy about something.”

“What?” Tasneem asked, not glancing up from what she was doing.

“I…don’t know. It’s registering stress somewhere, but it’s low-level and I can’t tell where it’s from. Dammit, that means it’s something small or it’s something overall, something pervasive.” She looked at the time and bit her lip lightly as she calculated. “I can’t do a proper check before work.” She looked up again and came to a decision. “I’ll have a quick look around before I go – can you keep an eye on the readings when you have time and let me know if anything significant changes during the day?”

“Sure, I can check at lunch, and I’ve got a break between calls mid-afternoon.” “Thanks, babe.”

Eloise did a quick scan around the walls inside the house, finished getting ready for work and left for the day, doing a circuit of the outside before heading for the tram. The electric rails carried her across the outskirts of the centre in fifteen minutes and a short walk brought her to the recycling depot. Eloise worked here two days a week, sorting historic plastics from landfills and incinerator stores, categorising it into project streams, depending on its condition and what it could be used for. It was messy and involved wearing PPE that got uncomfortable in Summer, but she felt good about it and was happy doing it for now. The other two days of the week she spent doing practical garden and landscape maintenance around the city gardens, green walls and green roofs.

At lunch a message came through from Tasneem: ‘Readings same as this morning.’ At three, another: ‘Readings same. Initial funding approved for wetland extension in park!’ She sent back, ‘Excellent! Well done xx’, and pulled her gloves back on.

Getting home late in the afternoon, warm and grimy, Eloise jumped in the shower, scrubbing quickly before enjoying the feel of the water for a few moments before the standard setting switched the water off. Rubbing her hair dry, she went through to the kitchen, where Tasneem was chopping vegetables.

“Want a hand?” Tasneem shook her head.

“No, don’t worry; I’m happy to make tea if you want to do a full house shakedown.”

“That’s great, thanks.” Eloise puffed out her cheeks, stood with her hands on her hips for a few minutes, then began.

The interface read the same as before. She took down the comms glove (officially known as a lichen interface glove) from where it hooked onto the display and slipped it onto her left hand, waiting until the small lights on the fingertips and palm lit up to show all connections were active. Beginning at the door, Eloise ran her gloved hand lightly over the surface of the wall, around the door jamb, windows, along the line where the wall met the floor, every so often sending out a questioning pulse through the glove, followed by an impression of comfort. It wasn’t like having a conversation – that wasn’t possible for two life-forms so different – but it was communication, and it worked, once you got your head around it and practised a bit, formed a bond. The fungus did recognise simple messages, and could respond in kind. The trick was interpreting the response.

Eloise asked it where the issue was, and told it things would be okay.

She ran her ungloved hand along the surface too, paying attention to its slightly yielding, rubbery texture, the subtle changes in colour, the wrinkles. Nothing inside, so she moved outside, went round the whole thing, lifted the skirts of the foliose edges and checked the pale, fluffy rhizoids as far as she could, then climbed the ladder at the back and canvassed the roof from the beams, picking off leaves and debris, enjoying the evening sun. Nothing came up as cause for concern. Hmm. She sat down with her legs over the edge of the building and thought. Something in the soil, the water? Something that blew through? It was probably fine, and whatever was causing the blip might just disappear, worked through itself.

Tasneem poked her head out the door. “You nearly done? Tea’s about ready.”

“Yeah.” Eloise descended the ladder again. “I can’t find anything. It looks fine, and it’s only a faint reading. Probably fine.”

Tasneem looked at her. “But you’re worried it might get worse if you don’t find the cause.” Eloise sighed.

“Yeah. But it won’t tell me where the problem is and I can’t see anything!” Tasneem thought for a moment.

“It won’t tell you where, as in it isn’t pinpointing a specific area?”

“Not even a general area.”

“Well…are you sure it’s actually a problem with this one? Stop me if it’s a stupid idea, but could it be picking something up through the mycorrhizae?”

Eloise stared at Tasneem for a second. “I hadn’t even considered that. Yeah. Maybe.” Tasneem disappeared back inside. “Hang on, just going to turn the heat off.” Eloise called after her, “Give me a hand to check the storage?”


The two of them headed out into the garden, Tasneem taking the storage box nearest the hose and Eloise taking the one at the far end. These were not very sizeable, big enough to store gardening equipment and suchlike; constructed from grow-your-own kits, they didn’t have an interface, but they were the same species as the house, so the glove worked on them.

Eloise was almost done with hers when Tasneem called, “Hey, what’s this?” Eloise checked the last part of the box and came back up the garden to Tasneem.


Tasneem pointed. “Here.” She traced her finger above a spot close to the ground where a whitish swirl marked the thallus.

“Hmm.” Eloise ran the glove over the patch. “Ooh. I think this is it. That’s definitely not happy. She got down on her knees and peered closely at the pale marking. “Shit. I think that’s infected.” She dug around the neck of her top for a moment and then pulled out a hand lens. Eyeing the lichen surface through the lens, she could see a meshwork of wispy hyphal growth, spreading in a narrow broken ring across the thallus. The area inside was grey and clearly not faring well. She groaned. “That looks like Athelia arachnoidea. It’s all cobwebby.” She sat back. “Crap.”

Tasneem got up and offered Eloise her hand. “Let’s go and eat, then work out what the next step is.” Eloise hesitated, but saw the wisdom of this. They ate while looking up pathogens in their home care book. Lichenicolous fungi could be a potentially serious threat to these houses, especially something like Athelia which had a wide host range.

“So, what are our options?”

“Well, the most effective option is to get rid of the storage box,” Eloise said. They were silent for a couple of seconds, then Tasneem said, “Or?” Neither of them wanted to destroy a living thing if there was another way.

“Or, we can try surgery, cut out the infected part and try and regrow or patch the hole. Or try to treat it with anti-fungal compounds – but they’re not that specific, so it’ll damage the lichen, too.”

Tasneem sighed. “None of those sound great.”

“No. But I think we should try removing the infected part, get rid of it completely. Anti-fungals might kill the patch, so we’d have to take it out anyway. And it looked like the Athelia was killing it anyway, so it kind of amounts to the same thing.”

“What would our chances be of getting allocated fungicide for it, anyway? Probably not high – more likely if it was the house itself.” “True. So. Surgery.”

“Yep.” Tasneem nodded. “We’ll have to let the neighbours know, so they can check their places.” “Oh, yeah.” Eloise got up and pulled on her jacket.

“I’ll come with you,” Tasneem said, standing up.

There were only four other lichen houses in their cluster so far, and all of them conversed on a chat group, swapping lichen info, articles and advice (and general gossip). But this was something Eloise and Tasneem felt it was best to tell in person. They approached the door of the nearest, an older couple they were friendly with.

“I hope they’re not angry,” said Eloise, as they knocked.

“Of course we’re not angry,” said Alex, after hearing the news, waving their hand. “These things happen, and we know you take good care of your place.”

Rakesh in house number two was less okay with it, clearly anxious at the thought of a pathogen nearby, and agreed that cutting it out was the best move. “Want a hand?” he asked.

The family in the third house seemed more interested than alarmed, and had to dissuade their daughter, Elsa, from going straight over to examine the fungus.

“You can come over when we’re doing it tomorrow, though, if you want,” said Tasneem.

The couple in the last house weren’t in, so Eloise left a message on the chat, letting them know what was going on and what time they planned to start the procedure the next day.

In the end, they had a party of seven gathered round the storage box late the next morning. Alex had brought a dish of dhal over, and Tasneem had fetched out flatbreads for scooping. When Flick saw the food, she sent Elsa back to their house to get a tub of brownies baked the day before. So, what could have been an unpleasant or stressful task was instead transformed into a neighbourhood picnic and get-together. Rakesh and Alex had brought their comms gloves, and while Eloise carefully cut out the affected section of lichen thallus, Tasneem, Rakesh and Alex held their gloved hands to the structure, transmitting messages of reassurance and comfort.

There was no display on the box to measure the lichen’s signals, but Elsa, holding both hands to the sides of the box, pronounced it okay. Eloise gently applied stimulant to the cut edges, fitted a grid on the inner side of the thallus and then covered up the section with a rehydrated dried lichen patch, clipping the edges together. It wasn’t exactly the right size, with a bit of a balloon of tissue, but maybe it would even out as the patch grafted on. Eloise covered it with a protective layer and sat back.

“Not so scary, was it?” Alex smiled. Eloise smiled back.

“Thanks, everyone.”

“Good practice for patching the house, if you ever need it,” said Flick.

“Pff! I hope that never happens…”

Once everyone had returned to their respective houses, Eloise patted the storage box and picked up her tools. Tasneem gathered the dishes and they headed back up into their home. The afternoon light shining through the wall turned it into a living painting, hues of green and brown mingling in seemingly abstract complexity.

“Hey, look.” Tasneem pointed to the interface display. The readings showed a happy lichen (if a lichen can be said to be happy).

Things were good, thought Eloise, warm with gratitude, as they sat down together. They were good.