Ruby Bolete (Hortiboletus rubellus) is a small, red capped, blue staining mushroom. It occurs in Europe, the United States, southern Canada, and Mexico. It reaches the western extent of one part of its range in eastern Minnesota. It is found in summer and fall in woodlands, parks, and gardens. It grows on the ground near oaks and other hardwood trees.
The cap is small, no more than 2⅜″ in diameter, and is bright but dark pinkish-red. This is the feature that gives the mushroom its common name. It often has a thin yellow or whitish band around the margin. The pore surface on the underside of the cap is yellow. It quickly stains dark blue when bruised. The stalk is up to 2¾″ long, is mostly red, and has many tiny red dots. When cut lengthwise, the flesh of the stem reveals numerous, tiny, bright red or carrot orange dots near the base.
Ruby Bolete is edible but it has a soapy taste, and like other boletes, it is often infested with maggots.
There are between 100 and 250 species of sap staining fungi, and they are divided into three groups. One of these groups is known as blue stain fungi. It is an informal grouping of various species of sac fungi (Ascomycota) that cause blue discoloration in the heartwood of trees without destroying the wood. The fungi are from the genera Ceratocystis, Ophiostoma, Ceratocystiopsis, and Grosmannia. They do not form a single taxonomic group because they do not descend from a common ancestor. Not all species in those genera cause blue staining.
Blue stain fungi spores are carried to a living tree on the body of a wood boring beetle. Their thread-like cells (hyphae) produce dark melanin on their walls to protect them from light, drought, and the tree’s own defenses. Blue discoloration spreads from the wound on the outside through the heartwood in a wedge-shaped pattern following the spread of the fungus. Boxelder trees produce a brilliant red stain in the wood as a response to the fungus.
Blue stain fungi damages the living tree by clogging the vascular system, leading to decline and premature death of the tree. The damage caused to the wood is merely aesthetic. The discoloration makes the wood undesirable and less profitable but does not weaken the wood.
Araneidae is a large family of typical spiders known as orbweavers. It is the third largest family of spiders. There are 3,067 currently recognized orbweaver species in 177 genera worldwide, 180 species in North America north of Mexico, and at least 44 species in 16 genera in Minnesota.
Orbweavers are found in woodlands, fields, and caves; on grasses, shrubs, and trees; and on buildings and fences. They are best known for the circular webs, called orbs, that they build. The webs consist of a framework of non-sticky threads (spokes) extending from the edge to the middle, and concentric circles of sticky threads winding to the center.
Orbweavers are very diverse in size, shape, and color. They have eight small eyes in two rows. The lateral eyes are usually well separated from the median eyes. The median ocular area (MOA), the area defined by the middle four eyes, is in the shape of a trapezoid. The front part of the body (carapace) is smaller than the rear part (abdomen). The abdomen is large, rounded, and marked with lines, spots, or zig-zag patterns. The legs are short and spiny. The first and second pairs of legs project forward, the third and fourth pairs project backward. There are three claws at the end of each leg, though these are not visible without magnification. Females are much larger than males.