Both the grains at the shaft tips, and the swelled, swollen stems of the plant when infected by smut fungus, can be eaten together. Both the「emerging shafts of orphaned children」and「emerging shaft of cucumber from child」might be considered a bit smutty and fungal-infested, lacking bathing facilities on a regular basis. Mushrooms are also fungi, hence that is one given meaning in Chinese. Perhaps refers to a vaginal infection after using a cucumber dildo. Perhaps refers to a bruised and soggy cucumber after having been used in such a case.
Glyph suggests that an orphaned female child in dynastic China needed a melon (cucumber) to learn about sex and open her hymen since she had no father…. SMUT as something obscene or indecent, or literally DIRTY as caused by soot.
Aquatic grasses grow with the base of the shaft deeply embedded in muck: plant with the brown heads of a bulrush, only child-size in proportion.「Bulrush child」as a tiny version the adult plant resembles brown WILD RICE, a grain that is not naturally sticky as is the usual type of white rice eaten in China and Japan, hence the element「alone, isolated」and the grains can easily be eaten one at a time, if desired, not so with sticky blob rice. Wild rice resembles loose「maggots in a melon」although not the most appetizing of imagery other than to a hungry bird.
Conditions faced by beggars may have in part been related to also being orphaned at a young age in dynastic China, and in any case, beggars are often isolated and alone, and dirty or smutty.
SMUT FUNGUS also propagates on the「stems of child (young) cucumbers and melons」as the elements describe. Frankly, nowadays the term SMUT FUNGUS tends to attract a different set of viewers besides gardeners when performing Internet searches, so「powdery mildew」has supplanted the well-worn SMUT FUNGUS in the vernacular, leaving photos of naked females sharing and enjoying cucumber dildos to the voyeurs:
「Powdery mildew can be a real problem in the vegetable garden, especially for cucurbits such as cucumbers, squash, melons and pumpkins. Powdery mildew is a fungus that forms as a white or gray powder on the leaves of plants causing the leaves to become deformed and die. It is far more probable in areas that are damp, are somewhat shady, and have higher levels of humidity. It is difficult to control powdery mildew once it begins spreading on the plant leaves. This makes it very important to use proactive measures in your vegetable garden to prevent powdery mildew from forming if you've had powdery mildew issues in the past. Here are some ways to prevent powdery mildew from overtaking your cucurbits.」
[ https://www.veggiegardener.com/threads/preventing-powdery-mildew-on-cucumbers-squash-amp-melons.1882/ 2023-05-17 ]

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: Zizania latifolia; mushroom
Japanese EDRDG: reed used for matting
Unihan extended: wild rice; Zizania latifolia