If so, please provide the verses. It would also be helpful if you provide a link.
Lingam-Yoni symbol was probably adopted by the Saivites later than the Vedas. The philosophy is same as that of Vedanta.
Why is Shiva worshipped as a Lingam?
The answer is that the Saivites use the linga form to signify nameless and formless aspects of the deity.
Sages said:- 8. Everywhere the deities are worshipped only in their image. How is that Siva is worshipped both in the image and the linga?
Suta said:- 9. O sages, this question is holy and wondrous. Here the speaker is Siva Himself and not any ordinary person. 10. I shall tell you what Siva Himself had said and what I heard from my own preceptor. Siva alone is Niskala (nameless and formless) since He is identical with supreme Brahman. 11. He is also Sakala as He has an embodied form. He is both Sakala and Niskala. It is his Niskala aspect that the Linga is appropriate. 12-13. In the Sakala aspect the worship of His embodied form is appropriate. Since He has the Sakala and Niskala aspects He is worshipped both in the linga and in the embodied form by the people and is called the highest Brahman.
Shiva Purana, Vidyesvarasamhita, Chapter 5
Where does the linga form come from?
The day on which I manifested myself in the form of a column of fire is the Ardra star in the month of Marga-sirsa (November-December), O children.
He who sees me on the day of Ardra star in the month of Margasirsa in the company of Uma and worships my Linga emblem or embodied image is dearer to me than even Guha (Kartikeya)
On that auspicious day (Sivaratri) the vision alone accords ample results. If he worships too, the result cannot be adequately described.
Since I manifested myself in the form of Linga emblem in the field of battle, this place will be known as Lingasthana.
O sons, this column without root or top will henceforth be diminutive in size for the sake of the vision and worship of the world.
The Linga emblem confers enjoyment. It is the only means of worldly enjoyment and salvation. Viewed, touched or meditated upon, it wards off all future births of the living beings.
Since the Linga emblem rose high resembling a mountain of fire, this shall be famous as Ruddy (Aruna) mountain. Many holy centres will spring up here. A residence or death in this holy place ensures liberation.
Siva Purana, Vidyesvarasamhita, chapter 9.15-22
What is the philosophical meaning of the Linga?
Shiva Linga according to Shiva Purana represents an infinite tower of light and is used to represent nishkala (formless) Shiva. Linga means mark. Shiva Linga simply means a symbol of Shiva. The Yoni associated with the Shiva Linga is simply the source. Just as Vedantins have Brahman - Shakti, Sankhya has Purusha - Prakriti, Shaivism has Linga - Yoni.
The Linga is equivalent to Brahman of Vedanta. The word linga is traced to two Sanskrit roots, li meaning to dissolve and gam which means to go, to be manifested or created. The Sivanubhava Sutra 3.3 defines Linga as follows:
That in which all mobiles and immobiles enter, i.e., get dissolved, and that from which the universe is created is Linga.
Sivanubhava Sutra 3.3
There are also mukha linga or Lingas with faces. Then there are vigraha Lingas where the full form of Siva is inscribed on the Linga. The faceless Lingas are called Sthanu Linga or Linga columns which form is traced to legendary material about Shiva given in certain Puranas like Linga Purana (ch 17), the Kurma Purana (I.26.68-99) etc where Shiva appeared as a column of fire.
Here are some additional shastra quotes.
Obeisance to Siva, the quiescent Brahman in the form of Linga whose symbol is wreaths of flames and is of the form of a column of fire.
Kurma Purana I.26.80
…The Linga is spiritual knowledge and is stationed in the hearts of Yogins.
Kurma Purana II.11.94b-95a
Linga and Yoni are also thought of as the Ardhanarisvara form of the Lord.
O highly blessed ones, at your entreaty I shall mention it to you after bowing to Uma and Siva.
She is the mother of the universe. She is named Bhaga. She is the three-fold pedestal of the deity in the form of a Linga.
Linga is the lord himself. O excellent brahmins, the creation of the universe is by both of them. Siva in the form of a Linga is the splendour stationed above darkness.
In view of the union of the Linga and pedestal he became Ardhanarisvara (Lord with the form of a woman in one-half). At the outset he created his son Brahma the four-faced Lord.
Linga Purana II.99.6-8
The Worship of Shiva lingam is totally vedic.:
Taittariya Aranyaka of Yajurveda gives us some mantras.
bhavÀyâ namaha bhavalingÀyâ namaha sarvÀyâ namaha sarvalingÀyâ namaha sivÀyâ namaha sivalingÀyâ namaha jvalÀyâ namaha jvalalingÀyâ namaha ÀtmÀyâ namaha ÀtmalingÀyâ namaha paramÀyâ namaha paramalingÀyâ namaha etathsomasyà suryâsyâ sarvalingam sthÀpâyâté pÀnimantram pavétram ( YajurVeda Taittariya Aranyaka 10:16:1 )
Rudra is man. Uma is woman. Prostrations to Him and Her. Rudra is Brahma. Uma is Sarasvati. Prostrations to Him and Her. Rudra is Vishnu. Uma is Lakshmi. Prostrations to Him and Her. Rudra is Sun. Uma is shadow. Prostrations to Him and Her. Rudra is moon. Uma is star. Prostrations to Him and Her. Rudra is day. Uma is night. Prostrations to Him and Her. Rudra is Yajna. Uma is Vedi. Prostrations to Him and Her. Rudra is Agni, Uma is Svaha. Prostrations to Him and Her. Rudra is Veda. Uma is Sastra. Prostrations to Him and Her. Rudra is tree. Uma is creeper. Prostrations to Him and Her. Rudra is scent. Uma is flower. Prostrations to Him and Her. Rudra is meaning. Uma is word. Prostrations to Him and Her. Rudra is Linga. Uma is Pitha (Yoni). Prostrations to Him and Her ( Rudra hridaya upanishad )
Ishwara Gita, Chapter-5, "Vishwaroopam Darshanam".
महादेवं महायोगं देवानामपि दैवतम् । पशूनां पतिमीशानं ज्योतिषां ज्योतिरव्ययम् ॥ ५.१२॥ पिनाकिनं विशालाक्षं भेषजं भवरोगिणाम् । कालात्मानं कालकालं देवदेवं महेश्वरम् ॥ ५.१३॥ उमापतिं विरूपाक्षं योगानन्दमयं परम् । ज्ञानवैराग्यनिलयं ज्ञानयोगं सनातनम् ॥ ५.१४॥ शाश्वतैश्वर्यविभवं धर्माधारं दुरासदम् । महेन्द्रोपेन्द्रनमितं महर्षिगणवन्दितम् ॥ ५.१५॥ आधारं सर्वशक्तीनां महायोगेश्वरेश्वरम् । योगिनां परमं ब्रह्म योगिनां योगवन्दितम् ॥ योगिनां हृदि तिष्ठन्तं योगमायासमावृतम् । क्षणेन जगतो योनिं नारायणमनामयम् ॥ ५.१६॥ ईश्वरेणैकतापन्नमपश्यन् ब्रह्मवादिनः । दृष्ट्वा तदैश्वरं रूपं रुद्रनारायणात्मकम् । कृतार्थं मेनिरे सन्तः स्वात्मानं ब्रह्मवादिनः ॥ ५.१७॥ Meaning: - Sages have darshana of Great God, Great Lord of Yoga, God of gods, Ishana, Pahupati, light of all lights (Supreme Light), holding Pinaka, remedies of all diseased beings, soul of Kala (Time), Kala of all the Kalas, Maheshwara, Umapati, having un-even eyes/vast eyes, Refuge of Knowledge and Detachment, eternal glorious, base of Dharma, hard to attain, worshiped by great Indra and Vishnu, praised by great rshis, source and base of all the energies, Lord of great yogis, Supreme Brahman, worshiped by yogis, situated in the heart of yogis, surrounded by yoga-maya. Sages of higher fortune witness the Unblemished Narayana who is in the form of yoni (Source/origin) of worlds getting one with Rudra (Who is in the form of Linga). Sages consider themselves fortunate to witness the glorius form of Rudra allied to Narayana (ShankaraNarayana / HariHara Form / Shiva Lingam).
Even in Mahabharata also.:
“sa eṣa rudra bhaktaś ca keśavo rudra saṃbhavaḥ | sarvabhūtabhavaṃ jñātvā liṅge ‘rcayati yaḥ prabhum | tasminn abhyadhikāṃ prītiṃ karoti vṛṣabhadhvajaḥ |” (MBH 7:172:89-90) “Kesava is that devoted worshipper of Rudra who has sprung from Rudra himself. Kesava always worships the Lord Siva, regarding his Linga emblem to be the origin of the universe. The God having the bull for his mark cherisheth greater regard for Kesava”.
I hope this clarifies your queries.
There is no mention in the Rig Veda or any of the other Shruti Vedic texts of the Shiva Lingam. There are, however, many references to the Shiva Lingam throughout the later Smriti
Linga and Yoni seem to be endogenous to the Indus Valley (p11, Introducing Hinduism, Rodrigues, 2006) whereas the predominate theory regarding Vedic peoples is that they came from the Caucasian area near Sintashta (the source of domesticated horses, chariots, Vedic burial rites, Indo-Iranian languages, and much of the Y-chromosome DNA of skeletal remains from the Vedic period). Thus, Sanatana Dharma is most likely a synthesis of local and Aryan religious practices. This is why linga aren't in the Vedas; initially they were only utilized by the local IVC—which left no known writings.