Previously in this thread: I argued that the *-it-s vs. *-ut-s alternation affecting 寐, 穟, 季 and 悸 in Shi Jing rhyming is due to a dissimilatory sound change in early eastern China turning *Cʷut-s to *Cʷit-s. To that end I began to assemble a word-family based on a root *Pˤut (where ‘P’ stands for either of *b, *m-p- or *m-pʰ), with dust-related meanings including ‘powdery’, ‘duster=broom’ and ‘comet’, out of ‘broom’. So far, the family includes 孛 MC bwot, bwojH ‘comet’, 勃 MC bwot ‘powdery’ (of soil), and 彗篲 MC zwijH ‘broom, comet’. I have described how MC zwijH was derived out of root *Pˤut through lenition of the original labial initial, voicing of the prefix, and dissimilatory shift of *Cʷut-s to *Cʷit-s.
I now examine the initial in root *Pˤut. Was it *b-, *p- or *pʰ- ? Consider 嘒 ‘to chirp, of insects’, OC (BS) *qʷʰˤi[t]-s > MC xwejH. This is an old word: it rhymes as *-it-s in Odes 197 and 222, and also occurs with the meaning ‘small-looking’ (as glossed in the 毛傳：“微貌”） in Ode 21 小星, at the beginning of the first line of stanzas 1 and 2:
嘒彼小星 ‘small are those starlets’ (tr. Legge)
The maning of 嘒 in Ode 21 cannot simply be ‘small’, as 小 occurs two words later. In that ode, a prince’s concubines compare their fate to that of a prince’s principal wife, describing themselves as faint stars in the sky. The idea is that of being faint, almost invisible, insignificant. Supposing the root in 嘒 ‘small’ is the same as in 勃 MC bwot ‘powdery’ (of soil), we may infer the more specific meaning ‘tiny as a particle of dust’. In order to evolve to MC xw-, an OC labial stop would have to be aspirated, and to be lenited intervocalically: *Cə-pʰ-. The evolution would be parallel to that of 彗, via *Cə-ɸ- (lenition) > *ɸ- (prefix loss) and finally xw-.
To my knowledge, this evolution path has not been proposed before. Are there any parallels ? the word 華 ‘flower’, MC xwae, is given the OC reconstruction *qʷʰˤra in Baxter and Sagart (2014) but this ignores 郭璞 Guo Pu’s comment to Fangyan 1. 7. 23 , that “江東呼華為荂， 音敷” (BS *pʰra); and the Shuo Wen entry for 葩 (reconstructable as *pʰˤra) : “葩, 華也”. It makes more sense to propose OC 【*Cə-pʰˤra 】 ‘flower’, with the same evolution as for 嘒: through *Cə-ɸ- > *ɸ- > xw- (I am using thick brackets【】for reconstructions that modify those in Baxter and Sagart 2014).
This parallel supports treating the root in 孛勃彗篲 as *pʰˤut, with the basic meaning ‘dust’ (v. and n.). 孛 ‘comet’, MC bwot and bwojH, then goes back to 【*m-pʰˤut 】 and 【*m-pʰˤut-s 】, where the prefix is the instrumental nominalizer called *m1c– by Baxter and Sagart (2014:55). A broom (out of which we may suppose the meaning ‘comet’ arose) is an instrument of dusting. 彗 and 篲, both ‘comet’ and ‘broom’, involve the long, iambic form of *s-, more specifically *s2-, a prefix deriving circumstantial nouns including names of instruments (Baxter and Sagart 2014:56), plus *m1b-, which turns a noun into a verb of volitional/controlled action: thus 彗 and 篲【*sə-m-pʰˤut-s】’instrument for dusting=broom=comet’. 勃 MC bwot ‘powdery’ (of soil) would have had *N-, the stative-intransitive voicing prefix (Baxter and Sagart 2014:54): 【*N-pʰˤut】. Finally 嘒 ‘small as a speck of dust’ had an iambic prefix of whose function little can be said: 【*Cə-pʰˤut】 . To recapitulate:
Root pʰˤut ‘dust (n.), to dust’:
孛 ‘comet’【*m-pʰˤut 】 and 【*m-pʰˤut-s 】> bwot and bwojH
勃 ‘powdery’ (as soil) 【*N-pʰˤut 】> bwot
彗篲 ‘broom, comet’ 【*sə-m-pʰˤut-s】> zwijH
嘒 ‘small as a speck of dust’ 【*Cə-pʰˤut】> xwejH
And, from another root:
華 ‘flower’ 【*Cə-pʰˤra 】 > xwae