लक्षणहेत्वोः क्रियायाः

The affixes शतृ and शानच् are substitutes of लट् (Present Tense) and come after a verb in expressing an attendant circumstance or characteristic and the cause of an action.
The word लक्षण means that by which a thing is recognised or known i. e. an attribute; हेतु means producer or cause. Both these words are attributes of the word क्रिया. Of lakshana:- as, शयानाः भुञ्जते यवनाः 'the Yavanas take their meals lying down'. तिष्ठन्तोऽनुशासति गणकाः । Of hetu :- as हरिं पश्यन् मुच्यते 'by (reason of) seeing Hari, he gets absolution'; अधीयानो वसति 'for the sake of study he dwells here'.

Why do we say 'when denoting a characteristic or a cause'? Observe पचति 'he cooks'; पठति 'he reads'.

Why do we say 'of the action'? Not so when the participle is the characteristic or cause of a substance or a quality. As यः कम्पते सोऽश्वत्थः 'that which is shaking is the Aswattha'; यदुत्प्लवते तल्लभु 'whatever floats is light'; यन्निषीदति तद्गुरु 'that which sinks down is heavy'.

Vart:- This participle also defines the agent of an action as, योऽधीयान आस्ते स देवदत्तः 'he is Devadatta who sits studying'.

Vart:- This participle is also used to state a general truth: as शयाना वर्धते दूर्वा 'the Durva grass grows in a recumbent position'; आसीनं वर्धते बिसं 'a lotus stalk grows in an upright position'. The compound लक्षणहेत्वोः of the sutra contradicts the rule by which a word of fewer syllables stands first 2.2.14. This shows that the rule 2.2.14 is not universal.