SporangiumA round case full of spores. It sits on top of a stalk.
SporangiophoreAn upright stalk that holds up a spore case.
SporesTiny grains that can each grow into new mold. They float off in the air.
StolonA runner that arches from one tuft to the next. Strawberry plants spread by runners too.
RhizoidsRoot-like threads that hold the mold to the bread.
MyceliumThe whole web of threads. It is the body of the mold.
HyphaOne thread of the mold. Stolons, rhizoids and stalks are hyphae too.
ColumellaThe dome in the middle of the spore case. The spores form around it.
ZygosporeA thick-walled spore made where two hyphae meet.
A hypha 4
Cell wallThe outer wall of the thread. It holds chitin, which stiffens it.
CytoplasmThe living material inside the wall. The nuclei lie in it.
NucleiThe mold's thread holds many nuclei. No cross walls divide them.
SeptumA cross wall that divides a hypha into cells. Bread mold hyphae have almost none.
How this list was compiled: Every name checked on 2026-10-02 and kept only where two of these use it. (1) G. F. Atkinson, Botany for High Schools, 1912, chapter 28, the bread mold or black mold, Rhizopus nigricans (public domain), https://archive.org/details/botanyhighschools00atkirich : a single thread of the mycelium is a hypha and a mat of hyphae the mycelium; erect hyphae arise in tufts and their ends swell into the spore case or sporangium; the stalk is the sporophore, sometimes called sporangiophore; an arched wall, the columella; rootlet-like threads called rhizoids at the base of each cluster; creeping hyphae that rise into the air and touch down again like the stolon of the strawberry; the mycelium is not divided into cells by cross walls and holds large numbers of nuclei; two branches meet at their ends and form the zygospore, whose wall becomes thick and rough. (2) C. S. Gager, Fundamentals of Botany, 1916, sections 250 to 254 and figures 185 and 186 (public domain), https://archive.org/details/fundamentalsofbo00gageuoft : the threads of mycelium are termed hyphae, largely or wholly aseptate, not divided by cross-walls or septa, with several to many nuclei distributed through the cytoplasm; stolons or runners like those of strawberries; hyphae that penetrate the substratum like rhizoids; a globular sporangium at the tip of each upright hypha, the sporangiophore; the central portion develops into a little column, or columella; the spores float in the air. (3) Wikipedia, Rhizopus stolonifer and Hypha, https://en.wikipedia.org/wiki/Rhizopus_stolonifer and https://en.wikipedia.org/wiki/Hypha : black bread mold; spreads by means of stolons; rhizoids anchor it to the substrate; unbranched aerial sporangiophores; spores; hyphae of compatible types make contact and produce zygospores; a hypha is surrounded by a tubular cell wall; cross-walls called septa; some fungi have aseptate hyphae. (4) University of California Museum of Paleontology, Fungi: More on Morphology, https://ucmp.berkeley.edu/fungi/fungimm.html : filaments called hyphae; fungal cells often have multiple nuclei; a cytoplasm lining; septate filaments are partitioned by cross-walls called septa; chitin in the cell walls adds rigidity. Licence: own work
The drawing: Drawn for this site on 2026-10-02 from plain geometry; own work, nothing traced. Licence: own work
How it works
To label and color the parts of Rhizopus stolonifer, start with the mold on its bread: round spore cases on stalks, runners and root-like threads. The second drawing cuts one thread open.
Read the full guide
From bread to spore case
The mold is a web of threads called the mycelium. A runner, the stolon, arches over the bread and touches down. There it sends rhizoids into the bread and upright stalks into the air. Each stalk ends in a sporangium packed with spores around a dome, the columella.
Label and color the parts of the hyphae
Each thread is a hypha: a tube with a cell wall around cytoplasm. In bread mold many nuclei share one tube, with almost no cross walls. The lower thread shows a septum, the cross wall most other fungi have. Print blank gives both drawings with numbered rings to label and color.
A zygospore forms only where hyphae of two compatible kinds meet.
Questions and answers
What are the parts of Rhizopus stolonifer?
Hyphae that together make the mycelium, stolons that run over the food, rhizoids that hold on to it, and upright sporangiophores. Each one carries a sporangium with a columella inside and spores around it.
What is the difference between a stolon and a rhizoid?
A stolon is a runner that arches through the air from one tuft to the next. Rhizoids are the short root-like threads that grow down into the bread where a stolon touches it.
What is the difference between hyphae and mycelium?
A hypha is one thread of a fungus. The mycelium is the whole mat or web that the hyphae make together.
Do the hyphae of bread mold have septa?
Almost none. The thread is one long tube with many nuclei in shared cytoplasm. Cross walls appear where reproductive parts form.